Cannot SET the Read-Only attribute

I have been using an [admittedly antique now] version control package for the past 20+ years (named QVCS). Roughly two weeks ago, it suddenly started reporting errors that I tracked down to its new inability to set a file's Read-Only bit when it is checked in. I'm currently manually fixing the read-only bits of files I check in, but I really want it to work correctly, as it has been doing on all versions of Windows since Windows 2000.

I've tried searching online, but I'm overwhelmed with hits about the exact opposite problem from people who cannot remove the read-only bit. In case they were related, I've tried several solutions, such as this command sequence in an administrator command prompt:


After rebooting, the issue remains. My biggest confusion is why only a single program would be affected by whatever is happening -- but I'm not really sure about that, because I don't have any programs that make things read-only. In fact, only ATTRIB from a command line and Windows File Explorer, both of which work fine.

Can (will?) anyone offer any suggestions about what could be behind this? Thanks!

This probably isn't a problem fixed with DISM.

Check if Controlled Folder Access has been enabled by mistake.

Thanks for the tip about Controlled Folder Access. Unfortunately, I am using ESET and not Windows Defender, and I have not enabled the ESET Folder Guard, which does the same function.

I have also written a test program and confirmed that I don't have any problem changing the read-only flag from my own code. So far, it appears that only the one program is being affected, and only when trying to SET the read-only flag. QVCS is not having a problem CLEARING the read-only flag when I check a file out.

When I'm seeing in its log isn't especially helpful to me, but maybe someone here will have an idea. It is logging this message (twice) just before displaying the error message about check-in failure:

Caught unknown exception in LogFileOperationCheckIn

Clearly the last thing there is one of the QVCS functions, but since the check-in succeeds in everything except marking the file read-only, I can only assume that, after 20+ years of working fine, it is suddenly getting an exception when trying to change the file attribute to include the read-only bit. Since I KNOW that the program hasn't changed, what could've changed in Windows to cause this?

Does it let you enable some kind of stack trace, so you can see where it's failing?

You could try uninstalling the last Windows Update (May 2025?), to see if it's a compatibility issue.

@pseymour No, it does not include any debugging features other than the activity log where I found that one error message reported twice with the same time stamp.

@garlin Frankly, uninstalling a Windows update kinda of terrifies me. This is my primary work computer and, due to the size of the drives a complete backup will take something like 60+ hours. Hopefully there may be other ideas before I need to try something that difficult.

Is this one executable or a set of them? One thing you can try is to go under File Properties, and run it in Compatibility mode for W7.

@garlin I'm pretty sure that it is a graphical shell for a set of individual CLI executables. I had already tried setting the shell to W7 compatibility, though I'm not sure why it should need that since it had been working fine on Windows 11 since 2019. But I tried anyway, in case MS made a breaking change to W11 (which would be a big surprise for something this fundamental.)

I'm probably going to be forced to try uninstalling the last Windows update as you suggested. I guess it is time to start making a full image backup of my boot drive. Sigh. Thanks for the suggestions! I was hoping this was something others had already encountered and found a solution, but alas, I seem to be unique this time. Oh well, it was worth a shot, right?

Well, you're using a VCS from 15 years ago. :)