Hi dis joe,

I have had the same problem and can confirm this to be annoying. The solution is rather simple though: go to your steam game file folder (something like c:programs/steam/steamapps/common/dayz) and open the properties of dayz.exe . Check the box to "run as administrator" and run the .exe .
This worked for me and also an firend of mine, should be fixed though as this workaround still doesn't allow to start the game via steam.

Hello dis joe,

Sorry to hear about your trouble. To begin with, please try performing the following steps:

1. Start Steam and right click on DayZ in your game library (make sure that the game is not running).
2. Select the tab labeled "Local Files".
3. Click on the button labeled "Verify integrity of game cache...".
4. Start DayZ once the process is complete.

Also, please try to run both Steam and DayZ as Administrator like steen suggests (make sure that neither Steam nor DayZ is running when checking the "run as Administrator" box in the Properties --> Compatibility tab).

The reason for you receiving this Windows error message seems to be due to either of the following:

• You do not have permissions to the file or the file location.
• The file is on a location that is not currently accessible like a network location or an external drive that is not currently connected to the PC.
• The file has been moved or deleted.
• The file or shortcut is corrupt.
• The file may be blocked by Windows.
• Your antivirus software may be blocking the file.

For troubleshooting this error message further, please feel free to have a look at the following kb article on Microsoft's site: https://support.microsoft.com/kb/2669244

Regards,
JStewart