"Open with..." is an add-on? I suggest checking with the developers of that add-on as to whether this is a known issue with their add-on in Firefox 96 and whether there is a known workaround.

Files opened in external application via the "Open with" dialog are saved to the OS temp folder and are set to read-only as a safety measure as you may lose edits if you re-safe the file to the same temp folder location.

Open with.. is how you open the file instead of saving it. It is not an addon.

If this is a new safety measure, why wasn't it in the release notes? Also, that doesn't answer my question about how to change it back.

Thanks, D

Normally links to file:/// URLs in http(s):// pages don't work at all, so it's possible no one tests that configuration during the alpha/beta cycle.

You can run a Mozregression to determine which patch changed the behavior. That does require time and bandwidth, but otherwise, you just need to specify the last good release version number (presumably 95) and first bad release version number (presumably 96 but you could use 97 just in case 96 misses the .0.1 through .0.3 releases), and test each build as it is downloaded.

See: https://mozilla.github.io/mozregression/

Bump - has anyone else had this problem and been able to solve it?

Thanks, D