Windows installation is slow because of anti-malware checks?

[Francesco Casella]

I have uninstalled and reinstalled OMC for Windows a zillion times in the last few years. After I switched to a laptop with a SSD, the time for uninstallation was cut drastically, to about one minute, because the bottleneck there was the physical HDD. Conversely, installing the software still takes about 20 minutes, which is quite a pain if you do it almost daily.

By looking at the process monitor, it seems that the bottleneck is Antimalware Service Executable, which runs around 12% - this is one full core on my 8-core i7-8550. The installation program hovers between 4 and 10%, which means, it is not running as fast as one core would allow. Transfer to disk is a few MB/s at most, and is never reported to be more than a few percent of maximum.

Is there any way to avoid the Windows anti-malware protection to scan each and every file that gets installed, so that installation goes as fast as possible? Is this perhaps related to #4829? If so, it may be a good reason to get a certificate to skip some of the safety checks during installation.

[massimo ceraolo]

On windows I rely on the built-in anti-malware of Win10.
Indeed I have much smaller installation times.
Today I updated my OM, on my PC i5-8400, and installed it on a magnetic HDD (not SSD). The installation took 3m9s.
However I installed only PowerSystems among system libraries.

[Francesco Casella]

I normally do not install any system library.

I tried to disable Windows Defender during installation; by doing so, the installation process takes 24% of overall CPU time (i.e. two full virtual cores) instead of 4-10%, and it takes a lot less time to install OMC, about 1m40s on my SDD.

I made a quick search to see if there is a way to automatically avoid this, but I couldn't. So, I will just manually disable Defender whenever I install a new nightly build.