Why can't Thunderbird save message filters )?

It is indeed very convenient to use the Thunderbird portable version. I changed a computer and copied it to use it. The most important thing is that everything is configured!
After the Thunderbird portable is copied, the basic functions, such as sending and receiving emails, are okay, but I don't know why. When I edit the message filters rule, although the newly added filter rule takes effect immediately, the filter rule list will be restored to the status before modification after the Thunderbird portable is restarted next time. That is to say, the newly added message filters are not all saved.
I tried it several times and the results were the same. I can't help wondering that the NTFS file format in Windows may be messy.
I tried to manually modify and save the message filters configuration file msgfilterrules. dat (for different Thunderbird versions, the storage paths of configuration files are different. For details, refer to the official manual). On my computer, the path is roughly as follows:
E: \ portableapps \ thunderbirdportable \ data \ profile \ imapmail \ 10.67.10.10 \ msgfilterrules. dat

The results show that the NTFS file format in Windows does not limit my permissions on msgfilterrules. DAT file access, and when I manually modify this file and add some email filtering rules, it can also be updated in Thunderbird. It seems that it is definitely another problem.
After many explorations, I finally found a solution on the official Thunderbird Forum:
Log out of Thunderbird, find and delete the tmprules. dat file in the configuration file directory (profile folder) of your account, and restart the file to enter Thunderbird.

Although I use the Thunderbird portable version, if this problem occurs in the normal Thunderbird version, you can solve the problem in the same way. Note that the configuration file path (profile folder) of your current account may be different.