Error - InLooxAddin.dll is not a valid Office add-in

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After the installation of InLoox, the following error ocurrs when starting Outlook:
“C:\Documents and Settings\ <userprofil> application data\Microsoft\AddIns\C:\Programme\InLoox\InLooxAddin.dll is not a valid Office add-in”



The problems results from incorrect data in the file “extend.dat”. Please ensure at first, that you have installed InLoox with a user account that has local administrator rights. Restart your computer and reinstall InLoox again to ensure a clean installation.   

If a new installation of InLoox does not solve the problem, an Outlook error is the reason; It can be solved as follows:

  1. Close Outlook.
  2. Find the following files, using the windows search function and rename them (activate search for hidden files!):
      "extend.dat rename to extend.dat.old"
  3. Start Outlook. You will receive the following error message:   
     “Error in registry for extension "Exchange Extensions;?”. The syntax or the format of the registration is not correct. Examine the registration settings and compare the registration entry with other extensions in the registration.“
  4. This error usually ocurrs only after you renamed "extend.dat" and start Outlook for the first time. If the error remains after several restarts, you can find a solution in the Microsoft Knowledge base at:
  5. Close Outlook and restart it (if necessary several times). The error messages should have disappeared and InLoox should work properly. If this is not the case, please contact the InLoox support at

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