“Microsoft Office 2008 for Mac cannot start because Microsoft Office is already in use.”

- MS Office 2008, 2009



When MS Office 2008 for Mac issues this message it means there’s another copy of Office on the home / office network running with the same serial number. It may also mean OS X Leopard’s built-in firewall may be turned off. If your built-in firewall is turned on when installing Office 2008 you will see the dialog box below on application launch asking you whether you will allow ‘Microsoft Word.app to accept incoming network connections ?’



Denying this request will prevent Microsoft Word being detected and going into System Preferences > Security > Firewall and selecting “Allow only essential services” or “Set access for specific applications and services” will stop Microsoft Word accepting incoming network connections and prevent the ‘cannot start’ dialog from appearing.



However, if you are a Microsoft Entourage user you must allow Entourage access to incoming network connections. It is an email client after all! Consequently Entourage users will have to find a new serial and reset the registration information of Office 2008.

To reset the registration information and serial number of Office 2008 for Mac you must quit all Office apps and delete the following files:

1. /Users/Your Home Folder/Library/Preferences/Microsoft/Office 2008/Microsoft Office 2008 Settings.plist

2. /Applications/Microsoft Office 2008/Office/OfficePID.plist

Now relaunch any of the Office 2008 apps and you’ll be prompted to enter a new serial and new registration information. You may also uninstall and reinstall Office 2008 to achieve the same end, although this is much more time consuming and relies on you having the installer.

1. Sabian, March 22, 2009:

   Great fix! Thanks so much for this. I was using Word for Mac on a college network and every time I went on-line to get info for my essays, I was kicked out of word! Very frustrating so thanks so much for taking the time to post this.

   Sabian UK

2. Kai Kai, March 28, 2009:

   NICE!! Thank you for this simple but useful tip.

3. Decdog, April 6, 2009:

   that’s really useful, much appreciated!

4. NEWMAC, April 13, 2009:

   THANKS VERY HELPFUL

5. NEWMAC, April 13, 2009:

   THANKS VERY HELPFUL

6. Michael, April 15, 2009:

   Hi..
   If I am not running another copy of Office on a network is is safe to accept incoming connections? Is there any reason that Word needs to access the internet?

7. Kirty Kedia, April 18, 2009:

   Great solution !! just had to replace the firewall settings n done !! thx

8. admin, April 27, 2009:

   Is there any reason that Word needs to access the internet?

   Not really. Word can be updated manually.

   If I am not running another copy of Office on a network is is safe to accept incoming connections?c

   If you have a license then certainly. If you don’t then it depends on who you are and where you are.

9. JB, June 8, 2009:

   This procedure worked well for me but the only problem is that the library files for Encore are not loaded and the method suggested by Adobe does not work. If you reload Encore as one of the procedures to fix this issue, you have to once again delete the cashe.db file to run Encore but the library files are still not loaded. If anyone knows how to get these files installed with Encore, please post here.

   Thanks for this really great effort and the great info!!

   JB

10. Glenn, July 15, 2009:

    Why does Entourage require incoming connections? It is an e-mail client, not a server. It initiates connections (via https/pop/imap) to request new mail from the server but I don’t see any reason why it should accept outside requests.

11. Titus, August 31, 2009:

    Hi Guys,

    I have two serial numbers on the two machines and still they shut down each other’s Microsoft Word Programs, too wierd, any help?

12. Teresa, September 13, 2009:

    Thanks,
    This was the easiest on-line help ever.

13. Andrew, September 16, 2009:

    Much appreciated!!

14. Chris, September 20, 2009:

    simple, brief, everything a computer user can ask for. great work.

15. kris, October 13, 2009:

    neat trick. works like a charm. thanks a lot for sharing.

16. Julio Cesar, November 12, 2009:

    i have recently dwnload the the trial version on the official web, can i use this trick and any serial?

17. joe, November 17, 2009:

    I just installed Microsoft office for mac. I will use entourage for email and occasionally access it from other computers when away on business. i will also use word to create documents for emailing. do i allow or deny in the “accept incoming connections” window? Thanks

18. britnie spears, November 30, 2009:

    firewall trick- awesome. i can keep stealing office. thanx

19. Chris, December 1, 2009:

    Titus,
    I have the same problem. I originally installed Office on 2 different macbooks using the same serial number, then bought a second copy bc I was getting annoyed everytime I kept getting shut out. But, after going through the prescribed procedures to delete the “plist” files and install the new code, followed by a complete uninstall and reinstall of the program, I still get the error message. It seems odd that I would have to block office from incoming connections to get around a problem that I legally should not be having. Please help, anybody!

20. el gringo, January 6, 2010:

    thanks !

21. Pavan, January 11, 2010:

    Thanks! This tip really helped me!

22. FSG, January 16, 2010:

    THANKS!

23. Tim, February 4, 2010:

    Thank s so much. I had the same problem than SABIAN. VGood work

24. babixling, March 15, 2010:

    THANK YOU SO MUCH ~ This saved me @ school…it seemed like I was fighting with someone else to use word in class and by doing this I am now capable of taking notes.

25. James, April 5, 2010:

    Saved my bacon. Thanks for the concise instructions. You are genius.

26. Cliff, April 7, 2010:

    That works AWESOME! Thanks!

27. tara, June 18, 2010:

    I get this message but when I go to the systme preferences it lists
    HP IP.app
    Microsoft excel.app
    Microsoft word.app
    Microsoft powerPoint.app
    safari.app
    Do I delete these? Sorry I am just confused?
    Thanks so much

28. steven midence, June 25, 2010:

    PERFECT THANKS FOR YOUR HELP SO GREAT

29. oy, July 19, 2010:

    Many many thanks

30. Joe, July 22, 2010:

    GREAT HELP!

31. Lyn, September 20, 2010:

    Thank you so much! You solved a problem I’ve had for weeks!! Your directions were easy to follow and worked perfectly.

32. Jamar, September 23, 2010:

    Thanks a lot for the tip. I was searching for a fix to this problem and am glad I found your tip. I kept getting this error whenever on the network at my college. Thanks to you, the problem is gone.

33. Tim, October 4, 2010:

    Perfect- thank you. I did not have the file referenced in step #1, but I did have the #2 file. I deleted it, and just like you said, I was prompted to re-enter the license key.