Can't Do Multiple File Copy Operations

If all else fails try the following: boot into Safe Mode according to How to use safe mode on your Mac and test to see if the problem persists. Reboot normally and test again.

NOTE 1: Safe Mode boot can take up to 3 - 5 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

NOTE 2: if you have a wireless keyboard with rechargeable batteries connect it with its charging cable before booting into Safe Mode. This makes it act as a wired keyboard as will insure a successful boot into Safe Mode.

Dechris_mode wrote:

I recently completed a clean install of Ventura on my iMac 2019. I started copying backed up copies of work files from a USB drive to my Mac hard drive. While that was happening, I tried to copy one PDF file to to my Mac drive and got an error message. I tried another file - Firefox dmg file and got the same error message. See the screenshot. I never had this problem with Monterey.

https://discussions.apple.com/content/attachment/8455d217-e468-4203-9454-5ed9f832ba31

The current Firefox installer.dmg can be downloaded directly

https://www.mozilla.org/en-US/firefox/new/

If you have FIrefox installed, the update process is via Firefox : About Firefox panel.