Kaspersky antivirus new problem.
just for forum information Calibre and Kaspersky antivirus are really incompatible.
As I have previusly written, startup time and books adding time is 10x slower than normal.
Now I have discovered something else. I have started 5 works to download Metadata. Well, I have activated the antivirus at the end of the second work the remaining 3 gave me error and were not executed.
Always Add Calibre Folder to your antivirus exclusion list.