TL is not designed to handle a large number of files. It will bog down and in time crash. It is free, but you get exactly what you pay for, a very antiquated out of date program that needs a complete overhaul.
I have had 2 crashes this month and lost a lot of my data, as back ups don't do anything for the top inventory folders or templates. They just get lost.
I have decided to go with inkFrog open to see how it goes. It has issues as well, but at least it does not crash and have your data lost.
I am now stuck with doing an inventory to listings check to make sure it is correct.