File type is stuck with the wrong icon

Give this a try: 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.

canecaster wrote:

Setting up a new Mac Studio and the ".dat" file type got assigned to a particular application (Kaleidagraph) when I installed it (I guess).

I want this file type to open in BBEdit, which I was able to do through the normal procedure (Get info, choose to open with BBEdit, and Change All).

While all my .dat files now open with BBEdit, the icon for this datatype is stuck with the Kaleidagraph icon. I've restarted the Mac, but the wrong icon remains. Is there any other way to fix it?

and what are your .dat files suppose to be in the icon?

what is the application do you want it associated with...(?)

I already answered this in your other duplicate post that Apple's Launch Services catalogs applications and the file extensions that they are intended to open. It then assigns the application icon to that document. That .dat data file is not what Launch Services associates with BBEdit, and thus regardless of the attempts to override the opening application, it will not change the assigned Kaleidagraph application icon.

I believe what happened is that yesterday (3/26), I attempted to respond to this post and the hosting software had a red fit and/or the site went away, and I never followed up until the current post (3/27) in this thread. This is probably your only post and I was mixed up earlier about it being a duplicate that I had responded to owing to how many posts I process each day.

Select one of the .dat files and bring up it's Info pane.

In the section "Open With" select BBEdit.

Then click on the "Change All…" button.