What are the exact steps you're doing when exporting the calendar? Screenshots may help.

Under events and tasks I check export calendar and it gives me 2 choices ICS or web page. I pick the ICS and hit export and save the file to my desk top. Then I email it to myself so that I can import it for my additional desk top. Or I even tried to save it to a USB. When I go to that file and click import the message always comes up the file is empty.

These are the 3 steps and you can't get past step 3 as the file says it's empty. It's being doing this prior to the last 4 updates. In the past you exported to a file name and them opened it and everything was entered into the additional calendar on my other computer.

Under events and tasks I check export calendar and it gives me 2 choices ICS or web page. I pick the ICS and hit export and save the file to my desk top.

That sounds exactly right, I'm doing the same thing.

When I go to that file and click import the message always comes up the file is empty.

What is the size of the exported file? Is it the same as the file transferred to the other computer?

Yes its the same size. This is only happening in TB. If I export to Outlook calendar it works fine. But I don't use outlook I only use TB. As I mentioned, this always worked never a issue before updates in TB back to the first # 10.

On the importing computer, is there anything related in the error console upon importing? Press Ctrl-Shift-J to bring up the error console. You can clear the console output prior to attempting to import the ICS file.

This is what it shows.

This is also what I got after trying it again

Chris Any solutions, I have not been able to import my calendar to my laptop or other desktop in about 6 months now.

Unfortunately I have no solution. My best guess what happened is that your calendar data on the exporting computer got corrupted somehow, and that this causes the import on the other computer to fail. Why this happened in the first place, I don't know. The closest I found in Bugzilla is this: https://bugzilla.mozilla.org/show_bug.cgi?id=1738611 But I don't think it's the same problem as yours. However, converting a HTML message to an event may have been the trigger. Did you ever do this? So after all, it's possibly a bug in Thunderbird Calendar, and all I can do is to suggest to raise a new Bugzilla bug for your problem. I don't think you mentioned your version of Thunderbird yet, that may also be an important information.

Chris, this all started when TB updated to 10, and ever since I have been updating my TB in hopes it would fix this issue. Currently running 102.10.1. Also, I have 4 different computers and everyone has the same issue when I have tried to export and then Import. The export shows it goes through to save, but it's the importing that shows a error and that it's empty on all my computers, except you can import it to Outlook. I also reformatted my lap top and reinstalled TB and that has the same issue, So I would say this is a bug in TB. I also noticed in a few previous help messages other people have the same issue and no one responded like you have to get this fixed. In addition, it would be wonderful if TB programed the calendar to sync on other computers that have TB just like the emails do and message do. I hope you can find a fix for this as I only like using TB as my email provider