Saving images as PNG files fails without any error message

Some quick thoughts:

“However, no PNG file is saved to the specified folder on disk.”   You can’t  have a folder open, save an image into that open folder and have it appear.  You need to close the folder / refresh the view to have it open.

Open the editor, log out of the editor. 
Unistall it.   Use whatever method you like.
Go to your adobe account and redownload whatever version you have from there.
Reinstall it.  

As the original poster, we’d like to add an addendum here.  We have also found that opening a pre-existing PNG file and making edits has similar issues.  We open the PNG in Adobe Photoshop Elements on our Windows 11 desktop and perform edits such as cropping and image resize.  We save the file back out and replace the old file (presumably), but nothing changes, none of the edits are saved.  When we reopen the saved file, it is the same as the original before any edits.  It is almost as if the Save As PNG engine never saves anything.  We have to save the file as a JPEG or some other format to save the changes.

Don’t use Save As

To save with transparency use:

File > Save for Web

From the pull down menu choose PNG24 - see image.

Save as uses whatever directory you last used:   for me it’s my download folder.

once you save as:    go to where ever you save it ( a folder of some sorts I’m guessing) and press F5.  F5 refreshes your screen.