LPX file size grows every time I save (with almost no changes) - WHY?

Question

Hi all,
I am just now starting to move from Logic 9 to Logic Pro X. I first imported a very simple file from logic nine as a folder project and did not import anything except the file.
- Then, I immediately saved it.  took more than 30 secs on core i7 - why so long?
- next I "saved a copy as" file 1a - file size 700k - nice and small.
- that I loaded the first logic X file back in and muted a few things and saved again
- I made some other very minor changes like muting and re-saved three or four times.
Here is what is strange –
Original file = 1 MB
main LX file was 2 megs and each subsequent save gained about 1 MB each time I hit save! So, the final grew to 6 MB after just a few saves!
I checked to see if there was some large edit history file I could purge – but it was empty because all I had done was change some mutes…
Q: what is going on with this large file size growing every time I hit save without any major changes – I would like to know what's going on.

Answer 1

It has to do with undo history, backups, and autosaves.  You can see these if you right click on the file and show package contents.  Explore in there and you should see these growing in the alternatives folder.  I would imagine there is kind of a limit to how many of these there are, but haven't looked to closely at it.