New to me Imac 27", problems with fusion drive

[Dr. Shafty]

Have 128GB SDD and 1TB mechanical. OS and applications mostly fill up the SDD, now I'm having ongoing 'insufficient storage' and 'scratch disk full'.
Trying to map things like dropbox and google drive to the mechanical drive.

I'm sure this is a noob question, so.. apologies in advance.

 

[honestone]

I would suggest you first run Disk Utility to try and help determine what is going on. For both of my Macs (late 2012 MacMini, and 2013 Mac Book Air), I just have 256 gig SSDs in each one. Also, I am not even using half of the space on each of those drives.

What, if anything, do you have on the 1 TB drive? Also, how much space is left on the 128 gig SSD? Are there any applications and/or data files that you could move from the SSD to the 1 TB drive?