Edit Enterprise Calendar in Project Online

Brass Contributor


I am running into the following error (screen shot below) when attempting to edit the "Standard" enterprise calendar or creating a new one.  I am able to open projects through Project Center by highlighting / Open / In Microsoft Project for Editing, so I know that Project is able to connect through the browser.  I have also tried in Chrome with the same result.  Has anybody else run into this issue?


 Enterprise Calendar.png

11 Replies

Hi Michael,


If you try it when Project is already open, do you get the same result ?  Are you using Project Professional Online rather than an older installed msi version of project ?  If so remove the msi version and download the latest version from the Office 365 portal page (CTR version). This type of error indicates to me that you ma have mismatched installs of the 2016 applications OR this error can manifest itself when you have multiple versions of Project installed. In which case the fi is as I already mentioned - install the CTR version (Click to Run).  Hope that helps.

Thanks for the response, Kelvin.  Yes, same result when I have Microsoft Project open.  And yes, I have the CTR version of Microsoft Project 2016 installed directly from the Office 365 site.  Also, I am doing it on a brand new machine that did not have any previous versions of Microsoft Project installed.

Hi Michael,

OK so now we established that, can you confirm that you only have ONE account set up in Project Pro that points to the respective Project Online environment - make sure too that it is set to default and that the account is set to automatically login to this account (so you don't have to select the environment you want to connect to. If you can normally login OK and connect from ProjectPro to your Online environment then working the other way around if something is not working it usually points to the fact that Pro is opening into the wrong online environment, or that there might be a hidden dialog somewhere that means you'll get the error you encountered until the dialog is actioned.

Of course I have assumed all along that you actually have permission to edit the calendar ? So for example you may have permission to open a project (which is why that works), and would be appropriate for a PM but not necessarily a permission to edit or create calendars which is a permission normally associated with an Administrator type account that has more elevated permissions.

Kelvin, thanks again for helping with this.  I previously had the Project Accounts set to manually choose, but set it to automatic and am still seeing the same issue.  Also, I am a full Administrator on the site collection and in Project Web App Administrator.  One other note that may help is that I receive this dialog box before I end up with the ultimate error:


Protected Mode.png

You should click allow on this dialog and for it not to prompt again.


One other issue that seems to be popping up randomly is the local corruption of profiles after updates. It's random so I've yet to discover a pattern but it looks just like this.


Note, the auto login has no impact on this particular issue if this turns out to be the case. In fact, to check for this issue, you'll have to revert back to selecting the login.


What I'd suggest is recreating the logins to eliminate this as a root cause. It's fairly easy to do anyway.


  • Login into Project Pro directly and select Computer when prompted.
  • Click blank project so that the Gantt is shown
  • File, Info, Manage Accounts
  • Delete everything except Computer
  • Close Project Pro
  • Now go to Project Web App, Project Center
  • Click the Project Ribbon
  • Select New, In Project Professional


This will take a minute as the connection information is automatically recreated for you and Project Pro is opened. Once the screen comes up, close Project and don't save the plan.


Retry your original action now.


Hope this helps.


Treb Gatte, Project MVP, https://tumbleroad.com

Thanks, Treb.  I just walked through your steps and am still seeing the same issue.  Also, I have checked on a couple of other Administrator machines and they are having the same results (all installed through click to run).

I have had this issue myself recently.

What helped me:

  • Open MS Project connected to the PWA
  • Open the PWA page in Internet Explorer
  • Mark the site as "Trusted Site" (Gear Symbol->Internet Options->Tab: Security->Select the trusted sites icon)
  • Set the security level of your trusted sites zone to "Medium-Low" (at least that's the level it is set to in my browser)
  • Then open the calendar

I hope this gives you the expected result.

Hi Michael,


I have the same problem. Were you able to solve this issue?




I have the same problem.  I've tried all of the suggestions above and still have no luck.

Really REALLY need this resolved as I have global regions giving me grief here.

My workaround was to try it with annother Webbrowser!

this worked for me as well - was trying in Chrome, but found Edge actually worked.