What kind of project? What kind of system? Are you current with your OS and AE? Too many unanswered questions to know for sure.
OS is windows 7, computers are:
i) z77, 2700k, 32gb ram, gtx570, samsung 840 512mb
ii) z87, 4700k, 32gb, ram. gtx780, samsung EVO 512mb
But I'm pretty sure it ain't a configuration problem, don't see a reason.
I just wandered on the web and saw that many people have the same problem but Adobe keeps on saying that everything is allright.
Just forgot: any kind of project, once opened and/or converted into After Effecs CC becomes a nightmare to save.
None of the ones I worked on had naive features like 3d raytracing or camera stabilize/track.
I'm talking about many layers with a bunch of filters (mostly for color correction), and some transform keyframes.
Files' average size is 10mb and tried to save on other disks (ssd or old fashion ones) but nothing changes.
Tried enabling or disabling disk cache (don't know why, but I did): nothing.
Tried to redoing projects from scratch on CC: nothing.
Tomorrow I'll migrate AeCC on another pc (dual xeon, gtx580, 48gb ram, raid5 on magnetic hdds) and test again.
Tried to disable everything in sync settings preferences (look to me something it could slow up savings): nothing.
Tried to disconnect from internet (same reason): nothing.
Moved an old AE5.5 project (windows 7, 2600k, 16gb, gtx570, crucial m4 128gb) in the AECC rig and converted: in AE5.5 takes about 4 secs to save, in AECC takes 47 seconds (!!!)
yesterday I tested on the third rig (see the post above) and the slow downs in saving persist.
Only thing is the projects have many layers and comps, to me seems something related to CC new indexing features..
Gonna shoot a video of my tests and share it so it's easier to explain.