melkaradawi2013 Some broken mods can block saving. Start by checking Previously Broken mods and CC and the current Broken and Updated Mods and CC thread to remove known issues that don't have available updates.
If you still have issues after that and checking for mod updates, do a test with NO mods, like this:
- rename the Mods folder and delete localthumbcache
- load your Save and do a "save as" to see if that save is saveable mod-free
- If it's NOT saveable, now make a new one and try to save, to find out if it's just that save.