@BlackCoffee please stop giving misleading and completely wrong advice.
I don’t know where you took the screenshot with “illegal” characters from but it’s just plain wrong. List of characters disallowed on specific file systems (not operating systems) is much shorter and hasn’t included # or space or a bunch of others since MsDOS times.
The # in URLs is not just allowed, it’s codified as fragment portion delimiter.
The schema URL field you are pointing to is not even used by KiCad, it’s there for people editing the file.
OP is describing intermittent problems that can not possibly be caused by the repository that is not changing.
@s.besso do you use an antivirus or firewall software (beyond the windows built in ones)?
I’m back with good news, that’s to say that the problem is resolved for good.
And which was the culprit? Another program that I’ve installed some weeks ago just to try it and that still uses an ancient installer (but also the program itself is a bit ancient). Do you remember those antique installers, seen mostly at the times of Windows 9x and Millennium? Those installers that when the program was uninstalled asked:
DLL blabla.dll seems to be not used by any program, delete it?
DLL blabla.ocx seems to be not used by any program, delete it?
etc, etc
Well, when I uninstalled this program I blindly clicked on “Yes to all” button. This action has for sure corrupted something in the operating system. No problems. I have restored the operating system from a backup image made just after the last clean installation (one year ago), updated KiCad to 6.0.6 (the image still contained version 5.x), updated the other few applications to the latest version and here I go. KiCad plugin manager works as expected and as the other two computers. Now I’m waiting only for Windows 21H2 to pop in (still not appeared) and then I will update the full image with an incremental backup, just in case.
Sorry for all the noise.
@qu1ck: yes I have one, and I have thrown away Microsoft Defender going back to ESET Security Premium. Too much flaws in the Microsoft product, for example files blocked by error that are impossible to restore from the quarantine, false positives, etc. I’ve never had this sort of problems with ESET.
