On Xubuntu 22.04 and 24.04 If a thunderbird mailbox is on a SAMBA controlled Ubuntu mount, starting thunderbird I am getting the error screen which begins:
Thunderbird is already running, but is not responding. To use Thunderbird, you must first close the existing Thunderbird process, restart your device, or use a different profile.
I've tried having 22.04 own the mailbox with 24.04 having access through a SAMBA mount to 22.04 - this failure on 24.04 - sucess on 22.04 (ie the system where it actually resides.)
I've tried having 24.04 own the mailbox with 22.04 having access through a SAMBA mount to 24.04 - this failure on 22.04 - success on 24.04 (again, the system where it actually resides.)
Accessing the SAMBA mounted mailbox which actually resides on Ubuntu 22.04 from a Ubuntu 16.04 has always succeeded and still does.
If I delete .parentlock - it still fails
I've had instances in the past of permission problems on a mailbox - permissions are wide open (set to 777 ie. wrxwrxwrx) on every part of the mailbox
I've checked for thunderbird running with ps -ef | grep "hunder" No active process contains that string.
My mailboxes are shared across several systems by being mounted at a specific mount location - always the same mount point on all systems. My Xubuntu 16.04 and my Xubuntu 22.04 are able to get to the mailbox. Only the new 24.04 is failing with this error.
I've tried the snap version and, a manual install from a Mozilla tar ball. Always the same failure.
Perhaps switch from a SAMBA type mount to a network file system (NFS) type mount.