So, I had no problems with Skyrim and since 2 days but one mod I was using started malfunctioning (didn't affect the gane, save or anything, the mod just had problems for its own attributes and I guess it started after I downloaded dawnguard but it could be a coincidence). I decided to verify the game, and I did. The mod starting working and everything went back to normal (mind you, I only have like 15-20 mods in contrast to the +150 mods people who had the problem as me on google which I couldn't get a working answer from). My problems is that my game crashes everytime I try to save or the game auto-saves. For example, if I auto-travel to somewhere it crashes when the save starts, but if I auto-travel to the same place while the auto-save is turned off, I can travel with no problem. It also crashes when I save it manually, so my point is that any thing that saves the game crashes it. I tried the following:
- Verify again.
- Re-start Steam.
- Re-start computer.
- Lower number of mods.
- Use removeallitems on my character for possible 'remnants' of deleted mods according to someone I found on google.
- Delete a bunch of saved files, because the huge number of saves I've had +800 could of been the reason.
- Check the ending part of save files and see if they didn't finish with .ess. No problem here since because they all ended with .ess.
- Deleted Japanese mods because some people say they might causethe problem.

It still crashes on saving, what should I do?
Also, I didn't download any new mods, and all my mods weren't causing any troubles before...but I don't know.

http://www.gamesas.com/topic/1402846-dawnguard-and-mods-bad-idea/

By saying "It doesn't matter if it worked previously" I'm guessing you're saying before Dawnguard, but mine were working with Dawnguard until I decided to verify, and the game opens with the mods working, it's just the save that doesn't work.

What Im saying is it doesn't matter if you start the game with mods and it looks fine, with Dawnguard installed mods WILL break the game at some point due to all the new data added to the title. Until a mod is updated to reflect these changes and make it compatible it is an extremely bad idea to use them, its a rookie mod user error.

Seriously remove the mods completely.