file is damaged and can’t be opened. You should move it to the Trash.

Disabling SIP is worrying.

Yes, I tried that as part of the troubleshooting process It did not work. Thanks for your suggestion.

+1

Disabling this for me seems to have worked as well.

Glad that technique has worked for you. I have not seen any reoccurrence after re-enabling SIP. Hoping it stays that way!

Best of luck to you.

I get the 'can't be opened' message, e.g.

“April Payments.numbers” is damaged and can’t be opened.

Done, but same result (only tried one file)

You didn't tell us what options you have when you choose "Open With" - does it give a list of apps?

I hope you are trying to open it with Numbers app? Your example was an Adobe app.

It gives the default app, and a list of others. Behaviour is true for all file types except (possibly) rtf and txt. Some files (maybe those created not imported/downloaded?) open ok.

Ok there's a number of standard diagnostics.

You should really start your own thread and describe a specific case in detail without flitting between file types.

That doesn't solve the problem, it just avoids it. The problem still persists.

And it is a problem with *your* Mac, not the OS as such.

I refer you to my previous response. This thread is becoming stale.

Thanks for your follow through on this issue, RiPC. Glad to hear you got resolution with the help of Apple Support.

A little RCA never did anyone any harm,.

wgrahame Said:

”file is damaged and can’t be opened. You should move it to the Trash.”

———-

Scan your Mac for Malware: 

Use MalwareBytes for Mac --- This is software that searches for malware/adware. Such software make your make act in mischievous ways(Technically). So, scan with it and then remove what is found. Once removed, uninstall MalwareBytes for Mac. Then restart the Mac.

Downloads:

1. Malwarebytes Anti-Malware for Mac
2. Malwarebytes uninstaller