Trouble with Preview -

Could be you Finder preferences file has become corrupt.

Click Go in Finder, click Go To Folder, type in ~/Library/Preferences/com.apple.finder.plist click Go.

A Finder window will open with the .plist highlighted, move it to the Trash.

Restart your mac, in Finder select a file and click command-i to get the info window up, select Preview as the default

app to open it with, then click on Change All so all docs of that type will open with Preview. Restart your mac and see if the setting has stuck.

grf819 wrote:

Since latest update - 10.13.1 - have had trouble with Preview app. I know how to set Preview as default pdf / jgp / etc reader - but Grab app keeps opening files no matter what I do.

Thanks!

That's weird. Grab can't open files even if you wanted it to.

Since 12.13.2 Preview seems to become invisible now and then, so the file I'm trying to open is opened with something else. If I use Control to get an "open with", Preview isn't even listed. It is still installed, and will return to normal, but it is very annoying while it's hiding. Grab is only one of the apps that try to open the file, some of them actually do.

Been there, done that. It fixes it for now, but it happens again. And if preview is still in hiding, it doesn't show up in the info panel, either. I've tried to make sure Preview is always running, but that doesn't seem to help. It's a sometime thing, things usually work properly.

Choose a file open the info panel select Preview, now have you also clicked Change All so all files of that type will now open with Preview?