I had this problem too w/MacOS X Yosemite 10.10.1. I didn’t want to decrypt my FileVault disk, and fortunately I didn’t need to. Interestingly as other users have reported, I did see a message somewhere that a JavaScript update was available & did I want to install it. I said no. I can’t find anywhere to install that update again; it doesn’t show up in the App Store’s update page.
My version of the fix comes from these Apple Discussion Forums, as well as info here: http://apple.stackexchange.com/questions/152271/user-update-needed-after-updatin g-to-mac-os-x-yosemite
Try the following.
1) Restart your computer. When the screen turns black, immediately hold down Cmd-R to boot to recovery mode. Go to Disk Utility, click your hard drive, and Repair Disk.
2) Restart. Login to your account. Launch Disk Utility. Click your disk & Repair Permissions.
3) Go to Apple menu: System Preferences: Users & Groups. Click your photo, choose a different picture, hit Done so the new picture saves. (In my case I also changed my password, although I’m not sure if that was necessary or not.)
4) Restart. All the Update Needed text over the names was gone, and all pictures came back.
5) Login to your account again. In Apple menu: System Preferences: Users & Groups, change your picture back to what you want. (And if necessary, change your password back to normal).
All seems good.
- Adam