What is the Purpose of these ETILQS files and can I delete them?

I have noticed that as of late, firefox (on my Vista machine) is creating a lot of etilqs files in my C:\Windows\Temp directory. Generally (as I understand it) these are supposed to be small temporary files that get emptied by firefox when you shut down. However, I am seeing numerous 100MB+ sized files in my temp directory.

What do these files do?

Is it safe for me to just go into that directory and delete them?

Solution 1:

Are you also running any anti-virus software? It is possible that these temp files are being 'locked' for inspection, and not being removed when they should be. Perhaps set your AV software to ignore *.etilqs files. I do not see any problem with deleting these files, as they are supposed to be temporary SQLITE database files.

Note: to check for handles on *.etilqs files, you can run Process Explorer and search for etilqs.

Solution 2:

In most cases you can delete files that are inside a tmp or temp folder and multiple days or weeks old.

SQLite is a portable database format. etilqs is sqlite backwards. Why backwards?

2006-10-31:  The default prefix used to be "sqlite_".  But then
Mcafee started using SQLite in their anti-virus product and it
started putting files with the "sqlite" name in the c:/temp folder.
This annoyed many windows users.  Those users would then do a 
Google search for "sqlite", find the telephone numbers of the
developers and call to wake them up at night and complain.
For this reason, the default name prefix is changed to be "sqlite" 
spelled backwards.  So the temp files are still identified, but
anybody smart enough to figure out the code is also likely smart
enough to know that calling the developer will not help get rid
of the file.

Source: https://github.com/mackyle/sqlite/blob/3cf493d/src/os.h#L52-L66