Auto update of file list

I have a collection of some 75000 tracks organised in about 5000 folders. I have been re-tagging a lot of files off-line, and I started a text file -> tag running. That's working well, but will take some time to complete on a very slow computer.
I also decided not to wait, and I renamed some files starting 1. 2. etc (ones that had already had their tags rewritten) to 01 02 etc so windows, Excel and mp3tag would agree on the order they should be listed in. I'd be able to rename two or three, then windows and mp3tag would seem to freeze for a minute or two.
My impression is mp3tag is attempting to synchronise its file name list with the directory structure. Right or wrong? Either that of I have a HDD which is having hiccoughs.
ta Derek

I have experienced the same behaviour as you did (or so it seems from your description) although I would say it takes about as long as to re-apply a filter. But yes, it takes longer than a renaming would do with the explorer.
I am not sure whether there is a remedy with the exception to load fewer files in one go ...