Disable QuickLook?

Do you actually mean QuickLook (pressing spacebar) or do you mean the Preview pane in a Finder window.

You can turn off the preview in the View menu.

If it is actually QuckLook, can you just not hit the spacebar?

It should not happen either way, but you might be able to avoid it until you sort out what is causing it.

Hello marcelfromgray,

To start off, we advise that you restart your Mac (Shut down or restart your Mac) and make sure it's fully updated (Update macOS on Mac). Once those are done, please test this issue.

If the issue persists, continue by testing to see when this behavior occurs. First, put your Mac into safe mode and test. Booting into safe mode will disable any startup and login items from automatically opening, which can help us to isolate the source of the issue further. When you do this, you’ll see some unusual behavior from the display; this is to be expected. Please follow the steps in this article: How to use safe mode on your Mac. 

Next, let's see if this behavior persists in a second user account on your Mac. Please follow these steps to make a test account that can be deleted later: Change Users & Groups settings on Mac.

Let us know how this goes, please. Thanks and have a fabulous day!

marcelfromgray wrote:

saving or reading a file from a network drive.

Indeed.

For any network locations, go to Finder > View > View options. Towards the bottom you will see "Show icon preview". Turn that off.

You only need to do this for network folders. But if you have a lot of those, you might want try the "Use as defaults" button. I'm not entirely sure what that option does. It might only take effect for new folders since it says "as defaults". If so, you will have to do manually do it for every network folder.

Otherwise, refrain from doing any manual QuickLooks. You can do a few, but eventually the Finder will hang. You can hold down the option key and click the Finder icon in the Dock to relaunch Finder.

Otherwise, be very careful about opening any files directly on the network volume. There are other bugs that can cause those files to get corrupted. The safest option is to copy them to your local disk, make your edits, and copy it back.

I am looking for "the Preview pane in a Finder window"

View menu, Show/Hide Preview. Cmd-shift-P

but WHILE I am already in an application from within the Creative Suite. Photoshop, Acrobat, InDesign, whatever still crashes the Finder.

No ideas. Sorry.