Like the booboo with .zip files, my installation of Snow Leopard was also having trouble opening .dmg and .pkg files. Installer.app would freeze. Bugger! After a little digging, the simple solution is to delete the “com.apple.finder.plist” file from your /Library/Preferences folder and log out/login or simply reboot. Fixed.

After updating my MacBook Pro to Snow Leopard, I noticed that I was unable to open .zip archives. I use The Unarchiver to open my Mac and PC-compatible archives. When I attempted to open a zip file, Unarchiver had been overtaken by Snow Leopard’s “Archive Utility”, and the Archive Utility.app kept freezing and required numerous Force Quits. I went through all kinds of debug actions, but nothing fixed the perplexing problem. I checked Google and found only one forum thread, but folks were suggesting that “Stuffit Expander” be used instead of Snow Leopard’s default utility. That’s not a solution, but a side-step around a critical booboo.

I recloned my hard drive and prepared to wipe everything and install a fresh copy of Snow Leopard. Literally on the verge of rebooting for the clean-sweep, I opened Disk Utility and ran the “Repair Disk Permissions” and “Verify Disk” functions.

Lo and behold, the zip archives are now opening with Snow Leopard’s built-in Archive Utility (which no longer freezes up). I re-installed Unarchiver and reset it as the default unzip app. All’s well, and I saved myself an evening of reinstalling all my apps. Phew!

If anyone else out there Googles “Snow Leopard won’t unzip” or “Archive Utility.app not working”, I hope they land here for the quick and easy fix.