[KevinH]

Okay I have tried something that may not help but it is worth a shot.

I have modified ViewPreview to use a deadline timer to prevent an infinite loop and then modified our WebProfileMgr to use a memory based cache that maybe can be shared.

I have pushed these changes to github Master.

So DNSB and DiapDealer, please give that a try on Windows and let me know if it helps when trying to use multiple instances of Sigil at the same time.

You will need to turn on the DEBUG log file in Windows via our environment variable:

SIGIL_DEBUG_LOGFILE set be a full path including file name to a "debug_sigil.txt" file on your Desktop (or someplace else you know where to look and have write access to) and look for this message in the output:

qDebug() << "View Preview Cache Clear failed - deadline expired";

That message indicates that the Cache clear failed and so we need to try a different approach.

I put that deadline timer in just to prevent a infinite loop.