I have T-bird version 128.7.0esr (64-bit) on both my desktop Dell and my laptop Dell. On the Desktop I have a message filter for removing common sources of spam/junkmail to the Trash. I tried to make that filter available by copying the msgFilterRules.dat file in the Imapmail folder of my desktop's T-bird profile under AppData/Thunderbird (I have a Windows 11 Enterprise OS...the laptop is Windows 10 Enterprise OS) to the Imapmail folder on my laptop's T-bird profile. After this copying process was done (with T-bird not running on the laptop) I loaded T-bird on the laptop, but the filter on the desktop did not appear under filters on the laptop. Note: while the email account for both T-bird installations is the same, the *profile name* is different. Perhaps that is the source of my problem. I *could* backup the T-bird installation on my desktop and then use that backup to install T-bird again on my laptop. But I wonder if there is a simpler solution that preserves the bulk of what is on each of these two T-bird installations?