Filters can be copied between accounts on the same or different computers. The rules are stored in the msgFilterRules.dat file, that is in the account subfolder named after the server name, e.g. pop.gmail.com.

Help/Troubleshooting, click Open Folder to open the profile folder, open Mail/<popaccountname>, ImapMail/<imapaccountname> or Mail/Local Folders to find the .dat file. Close TB before copying or pasting the file.

I have made multiple attempts with this solution and all have failed. I uninstalled Thunderbird and reinstalled before adding the DAT file and it still didn't work.

Any more ideas?

Thanks

If a filter involves copying or moving messages to specific folders, those folders must exist on the computer to which you are copying the filters. Check that you are copying the dat file into the correct account folder, and also make sure the filters on the desktop were created in TB on that computer, not on the mail server through webmail access. Perhaps post a screenshot of a filter that you copied but isn't working.