Does Windows 11 allow file associations for extensions that are more than 4 characters long?

Does Windows 11 allow file associations for extensions that are more than 4 characters long? When I follow the direct procedure to add file associations for extensions, I can do it for an extension that is four characters long, but not for an extension with more than four characters.

@comvox

I haven't tried directly adding file associations to my apps in Windows 11 Pro, but I do know that Windows is recognizing the .mrimg and .mrbak extensions as related to Macrium Reflect, which is my primary disk imaging application, so it must be possible. I also see other extensions of more than four characters in my file associations.

Perhaps others more knowledgeable than me will contribute to this topic.

Have a great day.

Regards,
Phil

PS: Welcome to ElevenForum.

I have some Themepacks on my drive that appear to have longer extensions.


I created a junk file in Notepad and gave it the same extension, it was saved.

Run "assoc" from the CMD shell, you'll see many file extensions longer than 3 characters.

There's a separate problem with creating your own extensions, because Windows protects file type associations from tampering with a security hash. Use SetUserFTA to get around it.

Windows 2000 has a 254 character limit.
Windows XP has a 255 character limit.
Windows Vista and Windows 7/8/10/11 has a 260 character limit.

file path, name, and extension combined do not exceed the operating system's maximum file name character limit

Thank you to everyone who replied. I appreciate it, and I'm sorry that It turns out that I was mistaken about what was the problem. What turns out to be the case, is that the problem was with one particular file association. I can now can get Windows 11 to do file associations for extensions of any number of characters, and have even learned several other ways to set them. But they all don't work on one particular file extension, .menufile. For example, if I use apps > Default Apps, then where a box should allow me to enter an application to run this file type, the box is grayed out. If I go in a file manager to, say, Books.menufile, and right click, and use "Open with", it only allows me the "use this time", not the "use always" option. If I right click and go to file properties, where there should be a "Change" option, it doesn't exist. I was wrong that this was because the file extension was more than four characters, but there's still a problem.

This is a file association which worked in Windows 10 and stopped working when I upgraded to Windows 11. As far as I can tell, every other file association went over unchanged. It is a file association of the ".menufile" extension to an application, a nice little file/application launcher which I named Onward.exe, which I created using Autohotkey. I presume this must have something to do with it. Or so it would seem except that another file association (with a seven letter extension) to Onward.exe was carried over without problem. (I have done a lot of checking since the problem with "menufile" arose and have learned a number of things. Thanks again to those who replied to me.)

I have made a file association to ".menu" which works, and then I made a change to the Onward program so it would process such files as if they had the ".menufile" extension. I still would prefer to make a file association to ".menufile" if it were possible.

comvox said:

Or so it would seem except that another file association (with a seven letter extension) to Onward.exe was carried over without problem.

Click to expand...

Could it simply be that Windows is protecting/restricting/rejecting use of the file part of the extension?

You're allowed to have multiple file extensions pointing to the same file type.

From CMD, run "assoc | findstr menu". Look for the current .menu entry.
Add a new extension using the same arguments on the right side.

assoc .menufile=[argument]