Marquee tool not working, disappears when finger is lifted from mouse.

Thanks.

Everything on mine matches yours, EXCEPT

I can't select "Selection Edges" (below "Layer Edges" in "Show" menu). It is pale and not available to select.

But everything in the "Show Extras Options" window matches yours, including "Selection Edges" (but I can't select it on the previous "Show" menu.)

...after checking and re-checking "Selection Edges" in the Show Extras Options window, I returned to the previous "Show" menu, and "Selection Edges" was now available and selected (checked).

So I tried to make a rectangular marquee, and the marquee appeared and disappeared, and its location coordinates appeared on the screen as it froze and the program crashed.

Hmmmm...  Odd.

I re-booted Photoshop and the exact same thing happened...

...And then I re-booted it one more time and tried again...

It didn't crash, and after selecting "Layer Edges" (instead of "Selection Edges") in the "Show" menu, the marquee appeared, and everything seemed to be working correctly.

I guess its working now,

but only after I :

1) go into "Show Extras Options" window and un-check and re-check ""Selection Edges"

2) go back to the "Show" menu, where "Selection Edges" is now checked, and check "Layer Edges" instead.

 ...and I need to do this for each image file when I open it.

[Removed] ! It just froze and crashed again.

End task and re-boot Photoshop...

When I open a file, "Selection Edges" is pale and not available in the "Show" menu ("Layer Edges" is checked), 

until I open the "Show Extras Options" window and un-check and then re-check "Selection Edges"

and when I return to the "Show Menu" it has changed and "Selection Edges" is now bold and checked,

...and I check "Layer Edges" instead, and the marquee appears.

...and sometimes it crashes. It's screwed up in some way!

(I've been messing with it for more than an hour since receiving your reply, and it acts a little differently each time. Usually I can get the marquee to work, and sometimes it crashes.)

I have used Photoshop extensively for more than 20 years, although I am not tech-saavy and rarely work outside my comfort zone. I have never altered or changed any of these settings and have only worked from the default setting. I've never had this problem.

Thanks for your help.