Hello everyone! I am OroCrimson. If you don't care about who I am or why I'm here, feel free to skip past this and check out the far more useful links below.
You can find me in the MUGEN community these days mainly as a screenpack creator for IKEMEN. The previous active moderator for MUGENFreedom deleted his account due to Reddit's API changes, which is very fair to be honest. I'm rather ticked by the way Reddit treats its users as well. However, I still feel like it's a good idea to have an open community for MUGEN available to Reddit users, so I've taken the wheel to get this ship back up and moving.
Please be sure to check out the new rules, and the new flairs. It is mandatory to flair your post if a flair is applicable, especially the Videos and Streams post as those tend to flood the subreddit and people should be able to filter those out if they aren't interested.

MUGEN Resources

Where to find MUGEN itself

There have been various versions of MUGEN released throughout the years. You can find the important ones here:
WinMUGEN
WinMUGEN Plus
MUGEN 1.0
MUGEN 1.1 Beta
IKEMEN GO

Which Version should I choose?

Short answer? IKEMEN GO.
Long answer? It depends, but newer is generally better.
WinMUGEN is the first version that people typically used, which a lot of legacy content was made for. This released in the early 2000s. It's fairly old, was not officially released, and has a fair amount of bugs.
WinMUGEN Plus is a hack of WinMUGEN that allows for higher res stages than WinMUGEN, but is otherwise the same. As far as I am aware, there is no clear reason to use WinMUGEN over WinMUGEN Plus.
MUGEN 1.0 was a new MUGEN release by Elecbyte in 2009, which adds support for HD assets and widescreen. It is arguably the most stable version of Elecbyte's MUGEN. It is also their only full release since LinMUGEN, before the WinMUGEN days.
MUGEN 1.1b is a beta update for MUGEN and the final release from Elecbyte. It added support for full color PNG sprites and for stage zoom. As it is a beta, it may be less stable than 1.0, although personally speaking I've not ran into issues unique to 1.1b.
IKEMEN GO is a fan-made open source engine compatible with MUGEN content. Due to being a custom engine, they've been able to create their own features for the engine beyond what's possible in MUGEN, such as an integrated tag battle system, 4v4 simultaneous battles, unlockable characters, or even story mode creation. MUGEN screenpacks and lifebars were not made for all of these new features in mind, so it is generally better to use an IKEMEN screenpack when using it, but otherwise is designed to be compatible with all MUGEN characters and stages (although some occasionally are not yet). It is the only one on this list with continuous development and that continues to improve, as Elecbyte abandoned MUGEN since 2013. As a custom engine, IKEMEN is also not beholden to MUGEN's copyright license, and therefore allows people to make commercial games with the engine (so long as the game doesn't contain IPs you don't own), so if that's something you're interested in, IKEMEN is your only choice.

Where to find MUGEN creation tools

The main software used for creating content for MUGEN is Fighter Factory.
There's two main versions that see use.
Fighter Factory 3
Fighter Factory Studio
Fighter Factory 3 is older but more stable and can do just about everything Studio can. Studio is newer but people regularly encounter crashes and file corruption while using it. You should only use Fighter Factory 3 unless you specifically need a feature only supported on Studio, and even then you should use FF3 any time you are not actively using said feature.

Where do I find MUGEN content? What other communities are there?

Other than searching the Content Release filter here, there are many other websites where you can find MUGEN content or a MUGEN community.
The Mugen Fighters Guild
Arguably the main hub for MUGEN creators and content. This is a forum where a lot of creators for MUGEN publish their content first and foremost.
MUGEN Free For All
A forum for people to discuss and share MUGEN content. A particular section of note is the COLLECTIONS topic, where people make forum threads compiling links to characters from certain games and franchises. Incredibly useful if you're looking to fill a collection from a specific franchise.
AK1 M.U.G.E.N. Community
Another forum for discussing MUGEN, notable for directly hosting and warehousing MUGEN content. It is very easy to upload and download MUGEN content here, and not relying on file hosting sites like Mediafire or Mega ensures a lack of dead links. Although the site runs a little slow due to being an independent site with a large audience.
MUGEN Archive
A very closed off and strict MUGEN forum that has been around since 2009. Like AK1, they store files themselves and warehouse the content. Due to their long time being around and their self-hosting, they have a lot of content that was otherwise dead-linked elsewhere on the internet. Due to their closed-off nature, its often the only place where such content can be found. However, account registration is mandatory to download content, they IP ban accounts without warning for unknown reasons (such as being seen associating with other MUGEN communities), they definitely IP ban you if they see you sharing files you downloaded from them outside of their site, and they block VPNs. If you can manage to get in and stay in, they're a fine enough place to download content— you won't get malware or anything— but generally they should be considered a last resort.
IKEMEN Go Discord
You won't find content here for the most part, but if you want to follow the development of the IKEMEN Go engine and/or content made for it, need help with certain things while using IKEMEN, or simply want to chat with fellow IKEMEN players and creators, this is a great place to go.

How do I use MUGEN?

I don't have any tutorials ready for you in learning how to use MUGEN, but plenty do exist across the web, especially on YouTube and the above communities. The easiest way to "use" MUGEN is to download a complete fullgame or compilation offered on the web and to play that. But if you want to build your own, then I do suggest looking it up.
In due time I may release my own tutorials here, or link to ones I find suitable.

What was the most characters you ever had in a MUGEN roster?
For me, I was in 7th grade (2009?) and successfully filled the classic 584-slot MUGEN Fighting Jam screenpack. Of course, it was filled with like dozens of Ryus, Gokus, Scorpions, and what have you. Also, I had plenty of shitty characters like Mortal Kombat Project originals and those terrible DBZ Hyper Dimension sprites. I also gathered about 500 stages from other MUGEN premade games.
However, I took a huge sense of pride and accomplishment finishing that damn roster at the time. This was before the days of MUGEN Archive, when you had to scramble every dark recess of the internet to find certain characters. Esnips, pressstart, Megaupload, Kazmer13's site with all the naked girls, all that junk. I still get an itch to do another roster more than a decade later.
What was yours?

So, im new to mugen and i wanted to make my own roster. I used the screenpack mugenmegamix black edition and download 2 chars (itachi & sasuke) and when i put them against each other the game would crash but if i put sasuke vs sasuke or itachi vs itachi it works fine... i can ofc provide the crash report but has any1 had this issue before and if yes how did u fix it?

1: What is MUGEN?

1A: MUGEN is a 2D fighting game engine originally released in 1999 by Elecbyte. MUGEN was originally designed for users to create games that matched the technology level of 2D fighters from the mid '90s. However, it quickly evolved to become highly customizable, allowing very fine control over each character's behavior. In fact, there are several custom games for MUGEN that don't behave like your typical 2D fighter. The majority of content created for MUGEN tend to be distributed as individual characters, stages or motifs (motifs are like themes, that control the look and feel of the game). Assembling MUGEN is as simple as downloading the content of your choice, and configuring MUGEN to know about it. MUGEN is designed to be used by people with little or no programming experience, but with some artistic talent and patience to learn. Of course, having some programming background does give you a bit of a head start. However, if you are just looking to play with downloaded content, all you need to know is how to unzip files and edit a text file.

2: Where do I download MUGEN?

2A: Right here.
MUGEN 1.1
MUGEN 1.0
WinMUGEN (Plus)

3: Where do I get characters/stages/screenpacks/full games/what have you?

3A: Most MUGEN communities(including this very subreddit) have a large selection of characters, stages, full games, and other types of MUGEN content to download, which is typically located in their "releases" section. However, we advise against getting this content from MUGEN Archive as it has been known to, among other things, lock some of its content behind account registration.

4: How do I make characters/stages/screenpacks/full games/what have you?

4A: With Fighter Factory, which can be downloaded here. Past that, there are several video tutorials if you need further guidance.

5: Why was this subreddit created?

5A: To provide a Reddit MUGEN community with competent moderation.

Originally posted on https://forum.freegamedev.net/viewtopic.php?f=20&t=13871
IKEMEN Go is a remake of the IKEMEN (open source fighting games engine that supports M.U.G.E.N resources) in Google’s Programming Language “Go”.
**GitHub repository: https://github.com/Windblade-GR01/Ikemen_GO
License: MIT**
I have stumbled upon this project during some random internet browsing fresh on this weekend, and already, it gave me some hope of making a more complete FOSS fighting game. To sum things up, this project is basically a FOSS engine clone of M.U.G.E.N (also known simply as MUGEN), a free (only in price, not free speech due to disallowing commercial use), highly customizable, 2D game engine designed by Elecbyte. At one point, there used to exist native Linux versions of this engine, but nowadays has become obsolete in favor of a Windows-only version. While are some other FOSS fighting game engines out there, most have not seen active development within the last yea365 days (IKEMEN GO has seen active development within the past month, that's one of the reasons I bring it here). With IKEMEN Go, we won't have to worry about having Windows installed, as it is possible to compile this for macOS, Linux distros, and possibly other Unix-like OSes, including BSD distros. :D
From https://mugenarchive.com/forums/faq.php:

[M.U.G.E.N.] allows you to build the game of your dreams, with all of your favorite characters. Its content is created by the community, and tens of thousands of characters, both original and from popular fiction, have been created. You can also create your own characters and skins, or edit the existing ones. If you are satisfied with your own creation, just share it with your friends or people worldwide, M.U.G.E.N has no limit.

The vast majority of content created for M.U.G.E.N. is derived from non-free copyrighted pop culture, but there also exists some original content. The one major issue that worries me, however, is that there exists little to no content for M.U.G.E.N. that is licensed under either Creative Commons licensing or OSI-approved licenses. :( Using IKEMEN Go with existing assets found elsewhere will likely result in a compilation that doesn't qualify to be wholly FOSS/Free Cultural. That's why properly-licensed assets (preferably under Creative Commons licensing that permits both modifications and commercial use) will either have to be made from scratch, or be converted from other existing ones. Additionally, a resource pack containing assets from the original M.U.G.E.N. is required (at https://github.com/Windblade-GR01/Ikemen_GO-Elecbyte-Screenpack) in order to run the engine after compilation is done. This resource pack is licensed under CC BY-NC-SA 3.0. A replacement graphics pack needs to be created if it is desired to eliminate as many non-free dependencies as possible, as even non-commercial licenses are not considered to be OSI-approved.
The M.U.G.E.N. engine currently utilizes SFFv2 as its primary file format for describing audiovisual assets. Specs of this format can be found at https://mugenarchive.com/wiki/MUGEN:SFFv2. A FOSS editor called NOMEN (https://sourceforge.net/projects/nomenedito) can assist in editing these files. It is licensed under GNU GPLv3, using Qt4 libraries, and development of it is inactive since early 2012. Its source code is also available as an attachment for archival purposes at the original post at the top.
Ultimate Smash Friends (GitHub repository: https://github.com/tshirtman/ultimate-smash-friends), despite being inactive for about 8 years, has some good assets that can be converted for use with IKEMEN Go (the exact version of CC BY-SA used is unclear, however). This includes the characters and stages, but not the music, as that is licensed under CC BY-NC-SA instead. For the music, OpenGameArt is likely to save the day: music, more characters, and more stages + other assets can be found over there for additional content to make a libre distribution of a M.U.G.E.N. clone. Of course, non-free copyrighted assets can be added in by end-users, but the burden will be on them if they choose to share their modified distributions.
Overall, I hope this M.U.G.E.N. clone gives hope to creating a more complete FOSS fighting game. Maybe I could try helping out by putting together the existing assets I have mentioned.

So I found this mugen screenpack on mugen archive and wanted to download it. After unzipping it and failing to get it to work I go back to the original post to see if there was any body else who was having my problem. However I saw mixed reactions to it. Two people directly said something about a virus and one guy was swearing at the poster but never straight out said anything about a virus. There were about 10 other comments which all did not mention anything about a virus. Some were saying good screen pack or asking questions about troubleshooting and even one of the moderators had commented on the pack. The post was made a couple years ago and about 2000 people have downloaded it with a like:dislike ratio of about 20:6.
I don’t know if I unleashed some kinda Trojan virus on my computer or not but I hope not, especially with so many other people downloading this pack from over 3 years ago. I don’t know if mugen archive doesn’t have a good virus checking procedure or not but I was told it was a trusted place to get stuff. I just don’t know tho. I did run the download link through a virus checker and nothing came up but I just want to be sure cause I’ve never really encountered a problem like this before

For reasons too long to describe, I've copied specific files and folders from my old Win7 laptop into a USB device so I can still access/use those files and folders. One of them is my entire MUGEN folder. This contains everything related to MUGEN (game, characters, stages, fonts, screenpacks, etc.) and it also includes some of the tools for editing stuff.
MCM is my main software for general editing. Sure, it's not the accepted-standard of Fighter Factory but for my purposes, it's good enough. The other one is ActEdit which I use to, well, edit .ACT files.
While MCM works fine, ActEdit won't run, giving me this message:

Component 'MSCOMCTL.OCX' or one of its dependencies not correctly registered: a file is missing or invalid.

Now, the context here is that I have "installed" it on my laptop and it ran fine. Sure, a few random crashes but nothing mayor. I say "installed" in quotation because I don't remember if I used the setup installer that came with the program or not. Then a few years later (to now), I copy it and the rest of the MUGEN folder into a USB device and now, when I run the program from the USB device, that error message appears.
Long story short, I wanna make it so that this runs from the USB device without much issue, if at all possible.
One more thing. Yes, I'm aware that Fighter Factory is an all-in-one program for MUGEN editing. I have it as another tool in case I need it. So why don't I use that instead? Well, for the past 3.5 months, I've been spending a lot of time using my university's computers which justifiably prevents activation of installation-type files unless the admin password is entered. Oddly, Fighter Factory was classified as such, even though the executable is to launch the program, not install it. Huh.

In an attempt to liven up this subreddit, I figured I would showcase some of the best (IMO) releases of the past few years. If people seem to enjoy this, I'll attempt to make this a monthly or possibly weekly thing. If not, I'll curl up into a ball and cry myself to sleep.
With so much content being released, I'm sure there's a bunch of great stuff I've missed, so feel free to add to this list. For now, I'm going to focus on character releases, but I'll try and add stages and screenpacks later.
Without further ado, here's my personal favorite current releases:
The Black Heart by Andrés Borghi
While The Black Heart was released a few years back, it is still an amazing game. It features custom-sprited characters and stages, along with some really fun gameplay. Each character has it's own charm, while remaining deranged at the same time. You can either download the entire game, or each charactestage individually to add to your Mugen game.
Solid Snake, Haggar, Squall, Sub-Zero, Mr. X, CM Punk, and Rorschach by SeanAltly
If you're not familiar with SeanAltly's work, he has been churning out very well-made and custom-sprited characters at a steady pace. He's also working on a full game, Capcom Vs. The World, which is currently in beta testing. Check out the progress here.
Goku, Vegeta, SSJ Goku, and Mr. Satan by Balthazar and Cybaster
Balthazar and Cybaster, or Team Z2, have combined awesome custom Capcom-style sprites with excellent coding to bring us some amazing Dragon Ball Z characters. Also on the site are some great stages, created by Daeron and NoZ.
Leo, Raph, Mike, Don, Krang, and Shredder by Dcat
Retro styled graphics with very fun, combo-heavy gameplay make these six TMNT characters must-haves for any Mugen roster. Also be sure to check out Dcat's stages.
Necro, Dhalsim, and too goddamn many others to list by Rajaa
Rajaa has released what is quite possibly the most accurate SF3 character for Mugen in Necro. His other releases such as Dhalsim, Amingo, Warachia, etc. are a custom-style gameplay, but excellent nonetheless.
Bluestreak by Diepod and Jesuszilla
Bluestreak is an original character, and the brainchild of the artist Diepod. Amazing sprites with excellent coding by Jesuszilla make Bluestreak a personal favorite. Be sure to check out JZ's other fantastic characters as well. To download, go to Downloads>Characters>Jesuszilla.
Deadpool, Cable, Gouken, Cloud, Krauser, and too many others by Mr. Infinite
Infinite has been on a roll lately, with top-notch releases nearly every month. Characters from many different games/brands, with a custom-styled gameplay that is smooth and fun, and all with amazing color separated sprites.
Ken, Kyo, Vice, Joe, Chun-Li, and Guile by Jmporphman
Jmorphman has released a slew of Capcom and SNK characters, with great coding, color separation, and custom sprite edits and gameplay. Be sure to get them all!
Mai, Skullomania, Psylocke, Jill Valentine, Sagat, Poison, Yuka, Kung Fu Man, and KungFu Girl by DivineWolf
DivineWolf is a relative newcomer to the Mugen scene, and has made quite a name for himself with these awesome releases. Skullomania, of Street Fighter EX fame, was sprited by the aforementioned SeanAltly (and also appears in CVtW). To download, go to Downloads>Characters>DivineWolf
Shaq, Angus, Giygas, Segalow, and many others by The_None
Looking to add a little diversity and/or insanity to your Mugen roster? Look no further.
Astonishing Cylcops, Thor, Wonder Woman, and Sandman by Loganir
Loganir made his return to Mugen late last year with the help of Verz36 in the form of Astonishing Cyclops. An excellent MVC-style character with custom sprites and all new moves. Be sure to check out Loganir's works-in-progress, including She-Hulk, Electro, and an update to Thor.
Captain Falcon, Dudley, Dr. Doom, and waaay too many others by Kamekaze
This dude has too much to even try and list, nearly 40. His MVC characters are fantastic, along with his Kaze-style. Hell, they're all very well done, so check them out.
That's all for now. I'll add more when I get the chance, and feel free to throw your two cents in.