P: Cannot save because the document is bigger than 2 gigabytes

I had the same issue. 
File in 8 bit. 
8.5 MB when saved in .psb
No masks
No hidden or large objects
What worked for me was during the save process, unticking the Maximize Compatibility box in the Photoshop Format Options pop up modal. 
Hope that helps. 
J 

In Photoshop, go to Image -> Mode -> 8bit then you save it. I hope this helps you.

The same thing happened to me and I figured out I was editing the image in 16bit but didn't change it to 8bit before trying to save it. This happened to me because, I had recently changed my settings in Lightroom to export into Photoshop in 16bit instead of 8 bit.

Can you save one of your files that you think should be smaller than 2GB (save as a PSB) so we can examine it for clues? (Post it to CC files or dropbox and provide a URL to download)

Often files are larger than you might imagine for valid reasons/

I believe this is a bug, I have the same problem since upgrading to the 2018 version of PS

I regularly have elements of my image outside the document canvas as I work in pattern so I’m doing repeats. My documents are usually quite large 7200x7200 or larger but the files are rarely bigger than a few hundred MB, I’ve been using Photoshop in a similar way for around 20 years and with similar document sizes for at least the last 8 years. Only since upgrading to the 2018 version of PS have I had this problem and it happens quite regularly. The document size reported in the PS UI is always less than 2GB, the only way to get it to save when this problem occurs is to remove everything outside the canvas and merger all the layers, even then it sometimes still won’t save. As others have mentioned, the problem seems to stem from having things outside the canvas which was never a problem in the past.

Choose Save As, then select Large Document Format from the Format pop-up in the save dialog. It will allow you to save a file greater than 2GB

I had this problem on a piece of art I'm painting and it's 18,000 X 12,000 pixels. Yes, HUGE! The problem is if you have ANYTHING outside of the base rectangle/artboard the "beyond 2 gigs" message came up. I place a layer filling it completely with color, then I clicked on that layer and any layer that had anything outside the rectangle. By using the cursor and "pushing" the "bunch" of layers up, down or to the side I could see what was outside the rectangle. To delete the unwanted stuff I used the selection tool to select that layer of color I filled, hit invert and delete the effected layer, repeat for each layer. Now, you need to repeat the whole process from the selected layer again and again as you "push" your layer 'bunch' around and around so you can delete all outside the rectangle. Once finished, I moved my layer bunch back to the rectangle and now it will save! Can you picture that? Should I make a video?

good It is definitely better to favor great internet Xender PC interconnection for downloading it this software on Bluestacks. nice.

The error message says to check 'saving and exporting' files, but the search function does not identify this topic

Try cropping the design... you may have file going over the canvas.. See 1st comment Chris Cox...