Photoshop Save for Web Command results in:

The operation could not be completed. The system cannot find the path specified.

Extremely frustrating. Wasted several hours trying to get this function to work again on the latest version of Photoshop CC 2019. All help documents and forums pointed to the fact that Photoshop was unable to access the Users\[username]\documents\ folder.

Either, the registry was set so the User’s document folder was on an unaccessible drive, or it was set to read only. Solution was to edit the registry to set the users document directory correctly, or remove the read only status of the documents folder. If you search the error message, you’ll find this solution in several places.

Nevertheless, this didn’t solve my problem, and it just randomly started happening recently. I uninstalled/reinstalled Photoshop, edited the registry, cleared off external hard drives, checked the document directory – no luck.

Then, I found cau.trindade’s reply on Photoshop forums. It solved it! Windows was at fault again. They recently did an automatic update and added more Ransomwear protection. Which, I’m all in favor of if it doesn’t kill other things without letting us know.

His post in full:

https://helpx.adobe.com/photoshop/kb/error—there-is-a-problem-with-generator–occurs-when-launching.html
After trying many options, I’ve solved this issue on Windows 10 Windows Defender Security Center.
In my case, the “Controlled folder access” was ON and for some reason it was denying access to a PS folder.

Try following the instructions below:

Open Windows Defender Security Center
Click Virus & threat protection
Click Virus & threat protection settings and click on “Manage Settings”
Scroll down to Controlled folder access and click on “Manage Controlled folder access”
Toggle it off

Good ol’ Windows Defender.