Half of my android contacts disappeared from my phone but are still in Gmail. Won't sync back I have a Samsung S5 (not rooted) linked to a single gmail account.  Several months ago I started noticing contacts disappearing.  I would attempt to call or text them and they wouldn't come up in the search.  It has recently gotten much worse (or maybe I just didn't notice before), but now roughly half of my contacts are now missing.

I can log into gmail via a browser and see them all there.  (I don't have gmail app on my phone).  I can add new contacts either in gmail or on my phone and they sync down within minutes.  However there are many of my old important contacts that are in gmail but will not sync to the phone.  I have even tried modifying a few and they do not show up on the phone.

I'm not trying to do anything fancy here.  It seems like some of these contacts are messed up somehow and I can't figure out what is going on. Another hint: at some point I imported a bunch of contacts into gmail via CSV file, but don't see any pattern with the ones that are having problems.
Thanks,
Eric
Check the groups the contacts appear in, in web Google Contacts. With some devices/settings only the contacts in "My Contacts" group are synchronised. (In some cases it's possible they are synchronised but not displayed or returned in normal searches.)

If this is the problem, moving the contacts back into "My Contacts" would fix it. 

You should be able to do this clicking Other contacts in the left panel, then the checkbox in the header row to select all, then click the Add to my contacts button. (If that button doesn't appear, click the groups button and check My Contacts.)