Calibre 7.x.x freezes randomly on windows 10

[gambit]

Calibre has worked on my windows 10 computer for several versions until 7.0.0, at which time it would randomly freeze 1 - 3 hours after starting it. I recently installed 7.4.0 (using the windows installer) and also downloaded the distribution to try and debug. Running 7.4.0 exhibits the freezing issues consistently. However, setting the CALIBRE_DEVELOP_FROM environment variable to the downloaded source area for the same version, 7.4.0, and then running ""C:\Program Files\Calibre2\calibre.exe" results in calibre running fine for days without freezing. Both startup methods show version 7.4.0 on the main calibre screen.
I'd like some insight on how the CALIBRE_DEVELOP_FROM environment variable affects the runtime of the executable to try and figure out what's going on...unless someone knows what might be causing the freeze itself.

[kovidgoyal]

That's because the freezing issue was fixed in master, aka the next calibre release, which is what you are running when you run from source.