Hi!

Here's my problem. For some reason snap to grid is not working even if it is currently turned on. Any idea how to fix this?

Thanks!

Interior or exterior cell?

A little more details

Hi! Sorry. Its for an interior cell.

make sure you set the first item you drop to origin (position x,y,z = 0, rotaion all 0).
it should synch up off that.
Make sure your settings in preferences are set to the interval and angle you want.

For building interiors with soitude pieces, I have been successful with snap value of 4 and angle of 90.
your mileage may vary

Hmm, tried setting the first item to origin point (0,0,0,) but snap to grid is still not working.

Have you tried the Shift+Q thing mate?

Edit: As in snap to reference?

Set the snap angle to 45 degrees. make sure the snap to angle button is active. try to rotate an object and see if it jumps by that. If it doesn't doesn't , then you do have a problem.
I'd try with a new piece or new cell.