I use Screen Capture on my Hackintosh to the point where it’s become instinctive. So, imagine my surprise when I suddenly received this cryptic error yesterday during my latest screen capture attempt:
“Your screen shot can’t be saved.
Unable to create type string.”
By golly, that’s both cryptic and non-instinctive (although, nowhere near as cryptic as Apple’s old “Type 11” error).
If you don’t use an Apple computer, or you’ve purchased AppleCare*, you can stop reading right now. Otherwise, read on:
After doing a little cursing and hair-pulling investigative diagnostic work I finally managed to restore the Screen Capture function. Below are the steps I tried, in nice tidy procedural order. Remember, this is provided for informational purposes only and comes with no guarantee whatsoever. After duly noting my disclaimer, read on:
Restoring Screen Capture on Apple OS X: Procedure
a) Is the Desktop locked?
- Go to: Finder –> Go –> Desktop –> Get Info
- Click the “General” tab.
- Uncheck the “Locked” box (it may be necessary for an Administrator to unlock the Get Info panel first).
- Attempt to take a Screen Capture (Ctrl + Shift + 3)
If that fails:
b) Have the Keyboard Shortcuts Preferences changed?
- Go to: Apple Icon –> System Preferences –> Keyboard –> Keyboard
- Click the tab “Shortcuts“
- Click the button “Restore Defaults“
- Attempt to take a Screen Capture (Ctrl + Shift + 3)
If that fails:
c) Does the Screen Capture Preferences file have a problem?
The Screen Capture’s Preferences file is located in ~/Users/<user>/Library/Preferences, where <user> is the specific name of the User, and called “com.apple.screencapture.plist”.
- Restart the computer
- Attempt to take a Screen Capture (Ctrl + Shift + 3)
If that fails:
- Launch Terminal.app
- Type: defaults write com.apple.screencapture type png
- Hit <enter> to modify/create a screencapture.plist
- Quit Terminal.app
- Shutdown and Restart the computer
- Attempt to take a Screen Capture (Ctrl + Shift + 3)
If that fails:
- Open folder ~/Users/<user>/Library/Preferences
- Does file “com.apple.screencapture.plist” exist?
- If it does, skip down to: “If that fails:”
- If not:
- Use Terminal (or, TinkerTool or OnyX) to see if the file is invisible and to make it visible. (NOTE: After making the file visible, make sure any files that should be invisible are restored to invisibility!)
- Restart the computer.
- Attempt to take a screen capture (Ctrl + Shift + 3)
If that fails:
- Drag file “com.apple.screencapture.plist” to the trash.
- Restart the computer.
- If the computer has multiple users, log into an account other than yours. OR: If you are the computer’s only user, create a new user and log into that account.
- Open Terminal
- Type: defaults write com.apple.screencapture type png
- Hit <enter> to create a screencapture.plist for that account
- Log out
- Log back into your main account
- Go to the folder ~/Users/<new account>/Library/Preferences
- Copy the file “com.apple.screencapture.plist” from the other account into your folder. (An Administrator may need to turn on privileges (apple+I) to get to the other account’s preference folder.)
- Attempt to take a Screen Capture (Ctrl + Shift + 3)
If that fails:
- It may be necessary to perform a “Clean Install” of OSX, which will require actual experts: See here for some guidance from Apple.
*or, get free tech support from one of your children 
Thanks for reading!
