Found on the web the recommendation to remove your .tlg file. It should reset when running a back up. Seems mine never did and grew to 11.6gb... you can delete it without problems, I did, not seeing a significant improvement on speed, but still 12gb of useless file is quite some space we can use for other stuff. Run the back up first, the tlg file can help restoring corrupted data, after back up is complete, delete that file