In Thunderbird, on startup, I get the error message: "Could not initialize the application's security component"

The message continues to check permissions of the profile, and free disk space.

df -h 

shows, that I have 19G free disk space.

find . -not -perm -644 -not -perm -600 -ls

shows: No file without rw-permissions for me.

Before the error occured, thunderbird worked well. But I changed my main mail-account. I had two, let's call them A and B, and used mainly A, but now I wanted to deaktivate it, and receive and send automatically via the second. I Had problems moving the filters from inbox A to inbox B (missing copy-functionality).

In the web, I found (mollazine) hints, to move key3.db, cert8.db and secmode.db out of the way, but it didn't work for me.

Another hint was to uninstall Quickcam(?. sic!), but I don't have Quickcam.

A third to recreate the profile, but I have subdirectories, filters, addressbook, groups - mails back to the year 2003. I don't want to risk the loss of data.

The whole errormessage is:

Could not initialize the application's security component. The most likely cause is problems with files in your application's profile directory. Please check that this directory has no read/write restrictions and your hard disk is not full or close to full. It is recommended that you exit the application and fix the problem. If you continue to use this session, you might see incorrect application behaviour when accessing security features.

When I open the error-console, it is empty.