The simple answer is Thunderbird does not share profile data with other instances. Issues like you are seeing are common in that scenario. This is especially so when dual booting is occurring between Linux and windows as they describe their file paths differently.

I understand. OK. But how can I get my folders back now the harm is done? How could I ask Thunderbird to check the folder structure to reincorporate the missing ones?

you could try moving the local folders files onto the local hard disk and then reversing the changes you made to share the local folders.

Additionally to what you have said, I am guessing we are talking about a network location or NAS you share from. This is another set of failures waiting to happen. Especially with large folders where the entire folder is getting dropped across the network each time it is referenced then copied back if it is changed.

Thanks for your quick reply!

Actually, everything is on my local hard disk. The idea (which has been working fine for a few years until a recent update) was that I updated the local folders (on both local hard drives of my 2 computers, one mac, one PC) and linked TB to the local hard drive folder on each of them. After updating on my Mac, folders started to disappear...

So, to be precise : all folders and sub-folders are on my local hard disk, but TB does not "see" them...

How many folders in total are we talking about? more than 500?

around 50-60 I guess

Hello there,

I still have the same question unsolved. How can I tell Thunderbird to cassess the subfolders inside the local message folder on my local hard drive? Some subfolders exist (and have been created by TB), but do not appear anymore in my "local folder" structure.

Thks for your help ! Martin