My browser / operating system: Windows NT 10.0, Chrome 84.0.4147.105, No Flash version detected

I have a scratch project I'm working on, but suddenly it just wouldn't save (I clicked “Try Again” countless times). I decided to download the project as a .sb3 file and just overwrite whatever the last save was with the .sb3. Upon opening up the project it was fine. After I uploaded the .sb3 file it was giving the “Project could not save” error again over and over. My connection and laptop are just fine, so I thought this strange. To be fair, the project is storing a bit of data (about ~100 items with 30 characters each in lists), but I'm pretty sure Scratch should be able to handle that. Any insight into my problem would be appreciated.

I believe I know what your issue is. Please try the following:

• Rename your downloaded project from a .sb3 to a .zip. (Scratch projects are just .zip files with a .sb3 extension.)
  
• Open the zip file.
  
• In the zip file, locate a file called project.json. This file contains all of the code in your project, along with what's in lists, and metadata about everything. Its size is limited to 5,250,000 bytes (5.007 MiB) - any more and your project will refuse to save. How big is project.json?
  

Flowermanvista wrote:

• In the zip file, locate a file called project.json. This file contains all of the code in your project, along with what's in lists, and metadata about everything. Its size is limited to 5,250,000 bytes (5.007 MiB) - any more and your project will refuse to save. How big is project.json?
  

The project.json file is ~5,243,676 bytes which is around the limit you showed. I suppose my endeavor is beyond what scratch is capable of; a shame I had to realize this so far in. Thank you for the info.