I’ve used TeamViewer in the past, and wanted to use it again. I launched it and was prompted to update, so I did. After installing version 7.0.11515 I used TeamViewer successfully and then the next day it wouldn’t work anymore.
“Access to the TeamViewer server has been denied!”
A dialog with that message would pop up over and over again. No amount of clicking “okay” would help. I kept thinking my password was being rejected, but it wasn’t.
What’s the problem? TeamViewer looks at your system’s serial number and tries to determine if it’s valid or not. If the app thinks it’s an invalid serial number, it will prompt that dialog, forever.
This can occur several different ways. For example, if you have been tweaking your Mac, you might have accidentally changed your serial number or erased it. It also happens if you’re running your own custom install of OS X, perhaps on PC hardware (aka a “hackintosh”.) Apps such as MultiBeast help one configure a hackintosh, but don’t provide a valid serial number. And to be clear, the number doesn’t have to come from Apple, it just has to follow a specific pattern.
What’s the solution? Get a valid serial number. How? You can use an app such as Lizard to generate a valid serial number. However, if you run this and apply it, it just might overwrite some other changes that it shouldn’t. So be prepared to fix your install if you go this route. For example, you might:
- Make a backup of  the /Extra/smbios.plist file
- Run Lizard
- Copy the generated serial number into your backup of the smbios.plist file
- Then replace the newly created smbios.plist file with your backup
There’s also another option. Others have also run into this issue and there’s a thread on InsanelyMac where a user has posted a copy of a smbios.plist file. You could grab the serial number out of it and use it, rather than using Lizard.