Help with problem opening

When I open Thunderbird I get this error:

“The messages could not be filtered to folder ‘Deleted on’ because adding a message to it failed. Verify
that the folder is displaying properly or try to repair it from the
folder properties.”

I cannot get past it. Clicking the ‘X’ or ‘OK button’ cause the message
to disappear very briefly before it immediately returns. I have tried
disabling add-ins with no effect. I’ve uninstalled, downloaded and
reinstalled TB with no effect. This indicates to me that this problem
is probably related to a Profile problem, but I don’t know that and
wouldn’t know how to proceed, in any case.

I’ve struggled to get to any Mozilla help or help forum. I realize that
most Mozilla products are open-source software and that there is no
financing for a tech support staff, but I thought that there was a forum
where users could search for their problem and ask questions to get
help. I’ve been unsuccessful. I can find a semblance of a forum by
searching for a specific issue but cannot find a way to sign on. All
credentials that I’ve tried have failed. Normally I would use Forgot
Password, but with Thunderbird inoperable, I cannot use that option.
Any help would be appreciated.

ALSO, I’m having trouble with my Mozilla VPN app. It will load but
immediately messages that an upgrade is required. When I click to apply
the upgrade, I get the message that the VPN will be inoperable while the
upgrade is taking place. I proceed anyway and the upgrade process
hangs, never completing. As with my TB problem, I can find no way to
get support for the issue. Mozilla VPN is a subscription with I pay

FWIW, I’m a bit frustrated with the inability to get either of these
issues addressed. I’ve been a Mozilla products user for decade or more
and have noticed that the process of finding support in any form has
become far more obtuse and difficult.

I don’t see where you say you tried repairing the folder from folder properties as directed by the error message.

  • Right-click the folder.
  • Select Properties from folder context menu
  • Use the Repair folder button

Thunderbird Support

Mozilla Support