More information would be helpful. Crashing can be caused by a number of issues:
- incompatible mods (solution: wait for mods to be updated)
- corrupted or improper settings in ini files (solution: delete or move these files and let new ones be created)
- uGrids not default (solution: add whatever uGrids settings you used before the update to the ini after the update is applied or ini files that are re-created)
The most direct way of identifying the problem is by disabling mods. If your game loads without crashing, you may re-enable mods one at a time until you find the culprit. If your save doesn't load, try disabling all mods and starting a new game. Then create a new save and try re-enabling mods one at a time.
If you use a large number of mods, you had better get used to either tracking each and every one of them for possible problems when an update is released; or disable automatic updates for Skyrim in steam so you can wait until all of your mods are updated
before updating Skyrim.
Saves made with one version may not be compatible with others, and such incompatibility may not even show up immediately.
While this may be true with any other game, this is not the case with Skyrim. Some quests may not function correctly across different game versions, but you shouldn't experience crashing or savegame corruption. This would certainly show up during the beta and would be addressed prior to release. Any cross-version compatibility problems are most certainly due to mods that are in use. This is not the game's fault. It is the responsibility of the mod author to update their mods should any compatibility issues arise.