Thunderbird, always on!!!

[Cool Buddy]

I recently reinstalled windows & as a result I had to reinstall thunderbird. However, after I put my data back in the profiles folder. It gives a message that thunderbord is already running but is not responding & I need to close it first. what is the problem?

[VexByte]

Make sure that there are no instances of TB in Task manager before copying the data to the profile folder.