Catalina 10.15.5 deletes nearly all my mails

[Mac Hammer Fan]

After updating Catalina to the latest version, all my mails from before 20 may 2020 are lost in my Telenet account, not in gmail. rebuilding the mailbox didn’t help. Mails from five year are deleted. What can i do?

 

[CalMin]

Restore from a backup?

 

[Niacchus]

After updating Catalina to the latest version, all my mails from before 20 may 2020 are lost in my Telenet account, not in gmail. rebuilding the mailbox didn’t help. Mails from five year are deleted. What can i do?

Ive been holding off upgrading to Catalina because of the mail issues. Curious, were you upgrading from 10.15.4 or Mojave?

 

[Mac Hammer Fan]

I was updating 10.15.4. I had never problems before.