So I'm not sure about the specific cause or fix on this, but I've had the problem before. It has to do with some versions of SAI when you have photoshop open at the same time as SAI. It also happens when you save a SAI document as a PSD and edit it with photoshop, then open it in SAI again ( or just opening a PSD in SAI ). Once you've done any of these you will have to save it in photoshop, it will not save in SAI.

My suggestion is do any work you need done in photoshop last ( such as text or gradients ). Do not have both programs open at the same time. I'm sure there are other more helpful fixes out there but this has worked just fine for me c:

ahhh, alright. thanks for the tips :3

Sure! Also an error message pops up when I'm in SAI and click OPEN FILE if there is a PSD in the folder I'm browsing. It doesn't do anything, just makes a noise and a message but you can just close the message.

That's pretty weird! Never had that happen.

Try krita

Krita would be best alternative.