Getting Google Calendar Sync to work with Outlook 2010

Edit [2010-08-17]: As per a comment from CB, the official Google Calendar Sync now supports 2010, although it still only supports 32-bit. Β If you’re running 64-bit Outlook and don’t want to reinstall to the 32-bit version, check some of the other options listed in the comments.

Since there’s no longer a need for the hack, I’ve removed all the instructions so hopefully people will just use the updated sync now πŸ™‚


99 thoughts on “Getting Google Calendar Sync to work with Outlook 2010

  1. OS Vista Ultimate. MSO2010beta. Your idea to Sync Calendar Rockzzzzzz…!!
    Any suggestion to sync contacts, notes…??

    Glad to Comment

  2. This is what I was looking for!! thanks a lot!! =D

    It’s really safe to mod google calendar’s file INSTEAD of modding outlook’s build number…

  3. Any idea if this will work for 64 bit versions of Outlook 2010 RTM?

    Trying to think up a way to test that won’t require hours of backing out if it doesn’t work but haven’t figured that out yet.

    • both should work fine for 64-bit as well (since the route of modifying the outlook binary is a version string, not code), but I’d stick with trying the modified calendar first.

      For testing it, just try the modified calendar sync exe – run it, create a new appt in Outlook called ‘foo’, create a new appt in google calendar called ‘bar’, then sync πŸ™‚ Backing out is just putting the unmodified .exe back into place (which you wouldn’t really need to do – the modification is just around a version check).

      • No joy. I tried it on a second PC and with 2010 64-bit Outlook and the calendar hack I get the following error when I try to perform a sync:

        “Could not connect to Microsoft Outlook tm: error -2147024156 …”

      • Thanks for all the work on this everyone. I have read all of the posts, but for the life of me I cannot find where to download the modified calendar sync. Can someone please point me in the right direction?


  4. Works like a dream – well done! I reckon it’s way easier to alter google sync than Outlook. I’m running Win 7 64 bit and Outlook 2010 32 bit.

  5. Using the hacked Google sync utility worked for me (Outlook 2010 32-bit) *except* that appts I accept from other people are not synced to Google. If I create the appt myself and sync it, it works fine. Anyone have a different experience?

  6. Great! I’ve tried both methods and the new Google Calendar sync code works better. For some reason, the hexed Outlook.exe file causes the system to run slowly.

  7. Office 2010 Pro final release 64 bit.
    It doesn’t work.
    google sync gives error:
    Could not initialize Google Calendar Sync add-in for Microsoft Outlook: Code 1011.

    • Yep, same here with the same configuration – this was from using the hacked copy of GCS, haven’t tried the Outlook hack yet 😦

      • Ditto here. “Could not initialize Google Calendar Sync add-in for Microsoft Outlook: Code 1011.”

        Office 2010 Pro Plus 64-bit
        Windows 7 64-bit

      • same here same code: running windows 7 64-bit: Could not initialize Google Calendar Sync add-in for Microsoft Outlook: Code 1011.

  8. Thanks for the fix. Worked fine for me w/ Win7 & OL2010 both 32 bit.

    I also did a binary compare using BeyondCompare and the only change I see is was what is described in this post.

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  10. SAME HERE…
    Office 2010 Pro final release 64 bit.
    It doesn’t work.
    google sync gives error:
    Could not initialize Google Calendar Sync add-in for Microsoft Outlook: Code 1011.

    • when i tell people i still use 32-bit apps (and in most cases, a 32-bit OS) and they ask why, it’s things like this that I point to πŸ™‚

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  14. Great blend of practical solution and technical schooling, though I don’t see a need to justify the later without leaving the rest of us a checksum to ease our concerns.

    • I thought about it, but when Outlook gets patched, I didn’t want people editing the patched version to get a checksum mismatch and freak out. Of course, that’s indeed another good reason (among others) to use the former route instead of the latter πŸ™‚

  15. I installed Office 2010 on Windows Vista x64 this past weekend and have been having a problem with Google Calendar Sync ever since. These are the most detailed, easy instructions to follow that I have found on the internet to address this issue. Thanks so much!

  16. Since the Google Sync application is the one with the problem, I agree that is one to modify. For those still afraid of downloading an exe, the information provided shows exactly what byte to change in the GoogleCalendarSync.exe via hex editor: navigate to 0002d580 and change 75 to eb.

  17. Thanks … a million thanks. I’m not a computer novice nor expert. I have tried everything everyone has suggested to sync google calendar with outlook 2010. This was easy and it works flawlessly. Thanks. Makes me mad at google for not doing this … obviously it can be done.

  18. I’m also dead now that I have Office 2010. Office 2007 worked fine with the havked version before.

  19. Can anyone get the the Google Calendar Sync hack to work with Outlook 2010 640 bit and Win 7 64 bit? I can not get it to work.

  20. Ignore my previous comment. The Google Calendar Hack seems to work. I had some issues with UAC that I needed to correct

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  22. Using the altered version of the sync tool worked for me! (32 bit)

    Thanks for collating that info, working it out and explaining so well.


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  24. Great that you guys figured it all out. Now for a novice like me I’m always looking for the easy way out. So has any one developed a litle downladable program to do all this? I’m runing windows 7 64 bit with Outlook 2010 32 bit. I would be happy to pay a reasonable fee.
    Many thanks in advance.

    • all you have to do is download the already-modified google calendar sync exe and replace the original exe with the modified exe – the part of manually modifying the Outlook exe isn’t necessary if you run the modified calendar sync

  25. For my w7-64 and OL2010-64 bit combination, I tried hacking either Calender sync or Outlook.exe and neither worked. Is there any workout for it?

  26. Thanks for the tip. It doesn’t quite work 100% for me though, and I can’t find anyone else having the same problem. Maybe one of you will know:

    When Outlook 2010 is open it will sync every 10 minutes in the background, no problem. But when Outlook is closed and it tries to sync every 10 mins a “Choose Profile” window pops up. I only have one profile, and even when I select the make default tick-box, sure enough 10 minutes later the window pops up again. This means that if I am not at my computer my it won’t sync automatically.

    Anyone come across the same issue? Would appreciate your help!


    • I’ve seen the behavior, but I’m almost always running Outlook so I haven’t really bothered with it (I also have multiple profiles).

      I’d imagine you could switch it over (to stop prompting) Start -> Control Panel -> User Accounts and Family Safety -> Mail and choose the ‘Always use this profile’ radio button.

      • Would you be so kind to explain how I would go about switching that over? Bit of a novice here!


      • Actually, I’ve figured out what you meant above. When I get to that option, it is already selected. There are two options: 1. Prompt for a profile to be used and 2. Always use this profile. The latter is what was selected, and still is. Still the same problem though…

        Any other ideas?

        • Darn – sorry that didn’t work – any chance there’s a second profile (check the drop-down) that’s maybe defined and not used? If so, delete it πŸ™‚ If not, I guess all I’d have left is ‘leave Outlook running’ πŸ™‚

          • Definitely no other profiles there. Annoying. Hopefully Google brings out an update soon! Thanks for your help though.

            • I found this by mistake. If you install MobileMe (from Apple), the profile prompt doesn’t come up. Weird. Not sure why that is, you don’t even need to configure MobileMe to do anything, just having it installed gets around this profile prompt issue with office 2010 x86 and this googlesync hack. I hope this helps someone.

              • WHAT THE F

                I was really skeptical of your workaround at first but decided to give it a try.
                That actually worked! It bought one last prompt but after that, no more.

                WOW. Thanks.

                For those of you wondering where to get MobileMe from without signing up, just search and download it on

                • Unbelievable but true. I just installed Mobileme and now Google calendar sync works without “choose profile” popping up.

  27. For me it has worked just fine with just hack google calendar, not
    was necessary to change the outlook.exe. I’m using MS Office Professional Plus 2010 32bits and Windows 7 Professional 64bits.
    Thanks for the tip! great job.

  28. Any old free (or paid) hex editor will do, so you don’t have to use notepad++ for this. I used HexEdit.
    Close your sync if it’s running first. Run HexEdit, open GoogleCalendarSync.exe (after making a backup just to be safe), find row 2d580 (the 00, as in 002d580 above, is not shown in all editors) chage 75 to eb, save over your GoogleCalendarSync.exe, and it works!

    • not sure why you’d do the change yourself instead of just using the already-modified version I linked to, but that would work too. πŸ™‚

      BTW, I mentioned “There’s tons of hex editors out there” in the second part when I actually made a change to an exe (Outlook’s) – I didn’t actually make any changes in the first part, I just loaded it in the editor to show what byte was different as part of trying to show people that the modified one that had been posted just changed a conditional jump to an unconditional one πŸ™‚

      • I also took the view that doing a single byte patch on a known .exe was safer than trying to do a compare on a downloaded file to see that the claimed difference really was the only change.

        Call it normal paranoia! πŸ™‚

        • BTW, great fix! Thanks.

          (And why couldn’t someone at Google change the original so the check allowed 2010 anyway!?)

          • Just to be clear, I didn’t make either fix – just tried to add a bunch of verbosity to the work others had done πŸ™‚

            There’s a few possible reasons why Google hasn’t made this change themselves yet – the reality might be some mix of these or something different altogether, of course.

            • I’d imagine the team that did the calendar sync has since moved on to become part of the Google Apps Sync which is a superset (syncing contacts, mail, etc).
            • Allowing the check to include 2010 means ‘supporting’ it, so having fully tested it and fixed any issues that arose. A friend personally hit a bug where meeting invitations didn’t work correctly (I forget the specific issue), and while there was a workaround for that bug, there wasn’t an actual fix yet.
            • Google has negative motivation to help people switch to or continue to use Office in general, Outlook in particular.
            • There’s already a viable workaround thanks to the jmp change πŸ™‚
  29. Works great with Windows 7 Ultimate, Outlook 2010 32-bit, GoogleCalendarSynch. Thanks.!

  30. Win 7 64, Office 2010 32 bit, using modified google sync.
    Is there anyway to adjust the sync frequency?
    Thanks for the great work…

  31. Google Calendar Sync exe file method is the way to go. Worked great for Outlook 2010 32 bit on Windows 7. Simple fix – why won’t Google release a similar update? Many thanks.

  32. I cannot get the zip file to run (1st part)… any suggestions??? There is no unblock in properties either… I need my calendar. Thank you for all your hard work.

  33. Windows XP Home SP3 – Office 2010 Pro Plus – Works great! I was weary of copying some random .exe file on to my system, but your succinct description of the .exe alteration allayed my fears and prompted me to take the chance… glad I did. Thanks!

  34. Hi

    I have downloaded the hacked google file, but I can’t launch the app- nothing happens when I double-click-Any ideas/help would be greatly appreciated? Windows Vista – office 2010 32 bit

    • you have to install the google calendar sync app first, and then afterwards you replace the .exe that it installs with the hacked one. If that’s what you did and it still won’t start, then I’m not sure what’s going on.

      Glad to hear the hacked-outlook.exe approach worked for you, at least πŸ™‚

      • Not sure why the first solution, didn’t work – followed all the steps – (installing the sync and replacing the .exe file with the hacked). Really glad it’s working now with the second solution. Thank you for posting this and for giving a really well-explained and easy-to-follow work-around πŸ™‚

  35. Fantastic, thank you very much, I do not now anything about computers or programming but I followed your instructions. Beautiful πŸ™‚

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  37. Works like a charm, thanks. I look forward to full Sync support for 2010 so I can go back to the developers exe. For now I’m very happy with these results, and appreciate your detailed post.

    • Nice! At least we can avoid this hack now πŸ™‚ This hack never worked on 64-bit either, so theirs is better, and at least supported πŸ™‚

  38. The new version doesn’t work if you are running Windows 7. Can you repost your hack for those of us that still can’t use sync.

  39. Google doesn’t seem to care.
    I asked a programmer to develop a software that will sync Outlook 2010 64 bit with google calendar. It will be distributed freeware, donations will hopefully keep the project running ;).
    At the moment we are still testing the alpha version, we should come out with a beta version within the week.
    If you want to be updated as soon as the beta is out, check the blog or subscribe to it:

  40. This works for me, Outlook 2007, 32bit.

    1) install autoit from
    2) paste the text below into a notepad window & save it as outlookProfile.au3 (change the Save As Type dropdown to All Files)
    3) double click the file.
    4)You may want to add a shortcut to your startup so you don’t have to run it each reboot. To make it run at startup you want to copy
    a shortcut of the file to the Startup folder on the Start Menu. C:\Documents and Settings\All Users\Start Menu\Programs\Startup

    While 1

    WinWait(“Choose Profile”)
    if (WinActivate(“Choose Profile”)) Then
    ControlClick(“Choose Profile”, “OK”, “Button2”)


    • WOW! Thanx for your post!
      in the past I’ve tried many times for syncing with google& office 2010 64 bit, now finally it works!!

  41. The calendar sync does not work, I saw the bit about control panel/family options…I do not have that in my version of 7 ..64 bit. It always prompts for a profile.

  42. hi, may29th .. has anyone found a stable way to sync outlook2010, win7, 64x? thanks

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