How do I prevent Preview from opening a file browser when clicked on the Dock?

You didn't share what version of macOS you are using, but if it is Ventura and later, check the following:

System Settings > <your avatar> > iCloud > Saved to iCloud [ See All ] > iCloud Drive > Apps syncing to iCloud Drive. If Preview is enabled in the latter, disable it, and then retreat from System Settings. That should end Preview by opening a File Chooser and just appear in the menu bar.

The last paragraph was and is the setting I have had on Ventura through Sequoia v15.3.2 and I do not experience any Preview File Chooser.

What do you want it to do when you open it?

It does that because there's no file for it to "preview". It's not like other apps - e.g. when you open a spreadsheet app it starts with a blank spreadsheet. Preview doesn't have a default file type (it can show pdf, jpeg, png, tiff, etc.) and it's not intended to be a file creator, it's a file previewer. Hence it can't show you a blank file when it opens because it doesn't know what sort of blank file you want, so it starts you off with a file browser to help you open the file a bit quicker. You can't change it so either live with it or open it by opening the file you want to work with, or just leaving it open all the time.

You could create a blank pdf/jpeg/tiff/png file and put that in the dock so it opens in preview when you click it, but the next thing you're going to have to do is open the file you want to look at.

Although you cannot reinstall Preview individually as it’s a built-in app, you can reinstall macOS to restore default applications:

• Before proceeding, ensure all your important files are backed up.
• Restart your Mac and hold down Command + R to enter Recovery Mode.
• Select Reinstall macOS from the options. This will reinstall the system files, including Preview, without affecting your personal files.

VikingOSX wrote:

System Settings > <your avatar> > iCloud > Saved to iCloud [ See All ] > iCloud Drive > Apps syncing to iCloud Drive. If Preview is enabled in the latter, disable it, and then retreat from System Settings.

It's interesting, I checked three of my Macs running Sequoia and Preview isn't listed in any of them.

This is from Sequoia v15.3.2 on my M4 Mac Mini Pro. Check my instructions above again, as hard to believe this panel would not show Preview on your Macs…

Here's everything in the panel except the Weather app. I had to do three screen shots.

Just to add, checked the better half's iMac running Ventura and Preview isn't listed there either.

It's not listed on my Mac either.

Not that it matters but QuickTime Player or Script Editor is not in my lists either.