screen shot not working on 2019 macbook pro with tahoe 26.0.1

I understand you are using the Screenshot app found in /Applications/Utilities.

Please confirm that Desktop remains selected in its Options > Save to contextual menu, as shown in the example below:

Even if it is selected and all the other options are set to you your liking, change that location to something else, such as Documents, and capture a screenshot. Same problem?

• If you find the screenshot in Documents, revert that change and test again. In fact you can change any of the options in that Options contextual menu (such as "Show Floating Thumbnail" etc), test, then revert the change. The idea is to force the Screenshot app to rewrite its stored settings which may have become corrupted for reasons unknown.

If you still experience the same problem, does it occur in "Safe Mode"?

Start up your Mac in safe mode - Apple Support

Boot Safe Mode, test, then reboot normally (not "Safe Mode").

Reply with your observations.

Refer to Take a screenshot on Mac - Apple Support.

Excerpt:

• By default, screenshots save to your desktop with the name ”Screen Shot [date] at [time].”

If they cannot be found on your Mac's Desktop then some non-Apple product may have interfered with that action. Dropbox for example has been known to do that. Certain apps do not permit screenshots.

SunBear0854 wrote:

Yes I know that. There are no other apps running, ...

As it turns out there are many other apps running.

John Galt wrote:

If they cannot be found on your Mac's Desktop then some non-Apple product may have interfered with that action. Dropbox for example has been known to do that.

So does "OneDrive".

I recommend getting rid of "Cocktail" also. It no longer serves any useful purpose. It's anyone's guess what it may have done to that system.

I understand screenshots do not save anywhere, even in Safe Mode. That rules out the possibility of third party app interference.

Download EtreCheck, run it, and post its report here. Instructions: How to use the Add Text Feature When Posting Large Amounts of Text, i.e. an Etrecheck Report - Apple Community. Be sure to do that after rebooting normally.

Upon examination of that report, and assuming none of us can find any obvious culprits, the next step would be to reinstall macOS because I'm out of ideas.

How to reinstall macOS - Apple Support

Reinstalling macOS doesn't usually fix anything, but it won't break anything either. Back up your Mac anyway as a matter of course.

Uncheck “Show floating thumbnail” in the screenshot app.

Tahoe seems to have togged it on.

SunBear0854 wrote:

Newer MacBook Pro 2024 model seems to work ok.

Do you have something installed on the 2019 MBP that is not installed on the 2024 MBP? Dropbox for example?

If they had the same problem I wouldn't have asked. I have Tahoe running on two different Macs, an M3 iMac and an M1 MBA. I have no problems taking screenshots with either. It has to be something local to your Macs. Unfortunately I don't have an answer for you.

Which of the several options described in Take a screenshot on Mac - Apple Support are you using please?

It is not universal.

Just tested SHIFT COMMAND 4 with my 2024 M4 Pro Macbook Pro running 26.0.1 with this page open and with current Safari:

I also have Dropbox running. Zero issues.