Can you run thunderbird ? If no and you get the error message as described by you, this is because a version is already running.

Open 'Task Manager' and see if there is a process 'thunderbird.exe' . If yes, then select and click on 'End Process'.

If there is no mention of Thunderbird program under 'Applications' tab and no mention of 'thunderbird.exe' under 'Processes' tab then it is likely there is a 'parent.lock' file in the profile name folder which is preventing thunderbird from running.

Perhaps you did not exit thunderbird correctly or it crashed or the computer shut down prior to allowing background processes to complete.

The application may have shut down abnormally, leaving the lock in place. To fix this, open the profile folder and delete the file,

• "parent.lock" (Windows),
• "lock" and ".parentlock" (Linux), or
• ".parentlock" (Mac OS X)

Access your 'profile name' folder and delete the 'parent.lock' file. then start Thunderbird.

• C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\
• More info: http://kb.mozillazine.org/Profile_folder_-_Thunderbird

Note: 'Appdata' folder is usually hidden, so you may need to make hidden folders visible first.

• More info: http://kb.mozillazine.org/Show_hidden_files_and_folders

Yes, I can run Thunderbird. The parent.lock folder was empty, but I deleted it anyway. I keep getting these two error messages over and over.

RE: Inbox cannot compact message

You appear to have allowed your Inbox to become so huge it is not possible to run compact folder on the Inbox to remove all 'marked as deleted' messages. There is not enough space to duplicate the Inbox to create an nstmp file necessary for compacting.

• Create some folders.
• Move all good emails out of the 'Inbox' folder into suitable folders for organising and storage.
• Delete any you do not want.
• When Inbox is empty, right click on folder and select 'Compact'.

I would also recommend you regulary compact the 'Inbox' and 'Junk/Spam' folder to remove all 'marked as deleted' emails and regain space in thoe mbox files.

The 'Inbox' is best used for new incoming messages and messages you need to repond/deal with, but do not use Inbox as a general store.

Usually, you do not need to move all emails out of the Inbox in order to compact the folder, but as your folder is so large, it is unknown if any corruption has occurred and so to be safe and not lose emails, I recommended moving all good and wanted mail out of the Inbox first.

RE: Thunderbird running message

Check 'Task Manager' Do you have two 'thunderbird.exe' processes running?

Do you two or more profiles in thunderbird?

Do you have more than one OS on your computer?

Is the thunderbird profile folder stored in the default location?