Outlook cannot read the calendar

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Yesterday Outlook (Microsoft 365 home premium) was working fine.  Today when I opened Outlook, it said “cannot read the calendar,” even though it actually could, as I determined by looking through the calendar.  Opening Outlook with the /safe parameter did not get the error initially but clicking on the Calendar icon results in the error, even though the calendar can actually be read as before.  The only add-ons installed are Microsoft’s own.  Also, near as I can tell, there were neither Office nor Windows updates applied over night.  The data file is not the culprit because it opens just fine when copied to my laptop and opened with Outlook there.  I uninstalled Microsoft 365 with the Microsoft Support and Recovery Assistant, then re-booted and re-installed Microsoft 365.  The first time I opened Outlook, the error did not recur, but it recurred on every subsequent time.  I’m baffled and at loss to know what to try next.

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Try CalCheck?

CalCheck is a program that checks your Outlook calendar for problems, and performs various checks on general settings, such as permissions, free/busy publishing, delegate configuration, and automatic booking. Then, each item in your calendar folder is checked for known problems that can cause unexpected behavior, such as meetings that seem to be missing.

Resolve Outlook for Windows issues with automated troubleshooting tools

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I wouldn’t expect CalCheck to fix the problem because (1) there is no error if I move the PST file to my laptop and open with Outlook there and (2) even on my desktop, after the error shows, Outlook displays the calendar just fine.

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You mentioned using Microsoft Support and Recovery Assistant to remove Office 365.

Did you also use that tool to fix Outlook problems, “I’m having problems with my calendar”?

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No, just to re-install Office.  First opening of Outlook was fine.  Subsequent openings got the “cannot read calendar” error again.  So far, not fixed.

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After banging my head against the wall, trying various things, I decided AskWoody MVP “B” undoubtedly knows a lot more than I do, so I decided to try CalCheck.  I’m getting an error message that is Greek to me:

ERROR: , Code: 0x8004010F, Function OpenMessageStoreGUID(lpMAPISession, pbExchangeProviderPrimaryUserGuid, &lpMDB), File CalCheck.cpp, Line 470
ERROR: Could not connect. Ensure you are connecting Outlook via MAPI to an Exchange server.

I don’t have an Exchange server, just Office locally installed.  B, can you give me a clue what I”m doing wrong.  TIA

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I expected CalCheck to work for you as your Microsoft 365 calendar should be on an Exchange server.

CalCheck works for me on my Microsoft 365 calendar (and just found seven minor errors which I corrected by deleting old appointments).

Your 0x8004010F error could be an Outlook profile issue:

Error 0x8004010F (when you try to send or receive email in Outlook 2010 or Outlook 2013)

Error 0x8004010F: Outlook data file cannot be accessed solved!

3 Methods to Fix Outlook Error 0x8004010F in Windows 10

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I have the same problem.  Outlook (Office 365) JUST DID AN UPDATE!!

Update 16.0.13901.20336

I am very sure this is the problem.

I tested this buy creating a new PST file and copied the exported calendar to the new PST and the SAME error happens.

Poor quality on MSFT’s part!

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I’ve been using build 13901.20336 for a week but I haven’t seen any calendar error.

Could you explain why you created a new PST to reproduce it?

(I think I’m probably missing something.)

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Tasks for the weekend – April 10, 2021 – change your Office @ AskWoody

Have you tried rolling yourself to semi-annual enterprise version? See the link I posted.

Susan Bradley Patch Lady/Prudent patcher

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My calendar problem is occurring in version .13901.20148, apparently an earlier version.

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Doesn’t that mean that you’re signed up for the Current (Preview) Channel, but you haven’t received the last five updates over the last month?

(Only the Preview channel received that build, and it was released on March 11th.)

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Also reporting this issue, seen after a Monday update, on 13901.20400 currently. Have two users with this so far, worried we may see more soon.

Not much troubleshooting yet, only tried Safe Mode and no effect on the issue. To-Do Bar Calendar on the right side curiously will keep the most recently added single calendar item listed and all recurring items. Any other one-off events are unlisted.

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Got any third party plug ins or something holding on to the pst file?  These are all pst’s correct?  Are they shared out from an unusual location?

Susan Bradley Patch Lady/Prudent patcher

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No PSTs, we block them because it fills up OneDrive storage typically. Set for Exchange with cached mode enabled.

We have a few add-ins like Mimecast, but I was under the impression Safe Mode disables add-ins and is a quick way to determine if they are the fault or not.

We may have been able to fix the issue. Doing a profile recreation and letting Exchange pull everything again fresh has removed the error & calendar items on sidebar are showing correctly again. If we reboot or anything and the issue comes back, will post again to alert.

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I’m having exactly the same problem. I click on ‘couldn’t read calendar’ and i then can see add/delete items to the calendar. I’m fed up with having to click ‘OK’ in the box.

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Have you tried to test your PST file with the tool, that is part of the installation of Office?
Its called SCANPST.EXE and it can repair “broken” PST files. It helped me lot of times. Simply select your actual PST file and scan it. It can take an hour, depending on your file size.

Im not sure, if you recreated your account from scratch, or you just keep copying the old one..

I tested this buy creating a new PST file and copied the exported calendar to the new PST and the SAME error happens.

But try the SCANPST.EXE first. Its worth trying.

But profile recreation is the best way by my opinion!

We may have been able to fix the issue. Doing a profile recreation and letting Exchange pull everything again fresh has removed the error & calendar items on sidebar are showing correctly again. If we reboot or anything and the issue comes back, will post again to alert.

Dell Latitude 3420, Intel Core i7 @ 2.8 GHz, 16GB RAM, W10 22H2 Enterprise

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I am having the exact same problem.  As there is no apparent fix at this point, I just try imagining the message doesn’t say “cannot read the calendar” but instead says “good morning”, “good afternoon” or “good evening” depending on the time of day.  I’m hopeful a solution will be discovered soon.

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[b]

There are many complaints about “Could not read the calendar” in Microsoft 365 Outlook at Microsoft “Answers” over the last six weeks:

Microsoft Outlook Error: Could not read the calendar

Outlook error message – “can not read calendar”

Outlook “Could not read the calendar” pop-up April 2021 after Office 365 Update 16.0.13901.20336

Could not read the calendar message

The best information was published in a Slipstick.com newsletter a few days ago:

Could not read the calendar

Several users are reporting a calendar error: “Could not read the calendar“ when they switch to the Calendar or to the Inbox. The appointments display properly and the usual fix for this error – reset the view – does not fix the problem.

Turning off the To-Do bar calendar reduces the number of times the error dialog comes up. Keeping the calendar open in a separate window so you don’t need to keep switching between the Inbox and Calendar will also reduce the number of times you see the error message.

Microsoft is investigating this. In the meantime, if you are affected by this bug and the error is too annoying, you can roll back to an older version of Office.

To rollback, type cmd on the start menu, right click on the Command Prompt, choose Run as Administrator then copy and paste the line in the command prompt. (This is a March 30 2021 build)

“C:Program FilesCommon Filesmicrosoft sharedClickToRunofficec2rclient.exe” /update user updatetoversion=16.0.13901.20312

I have more information on rolling back Office installs and the complete command to use at Uninstall Updates in Office ‘Click to Run’ (slipstick.com)

Exchange Messaging Outlook – April 15 2021 – Volume 26 Issue 10
A weekly newsletter about Microsoft Exchange and Microsoft Outlook
by Diane Poremsky, Outlook expert and Microsoft MVP

I’m not yet convinced that rolls back far enough. If I was going to revert to an earlier version to avoid the error message I would use version 16.0.13801.20294 from March 9, 2021.

• This reply was modified 4 years ago by b. Reason: Corrected date on last line from March 1 to March 9

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And put yourself on the semiannual channel while you are at it.  (see last weeks tasks post)

Susan Bradley Patch Lady/Prudent patcher

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The error goes away reverting back to 16.0.13801.20294

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b

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My apologies for not responding sooner to all the good folks who were trying to help.  I was doing a bunch of testing with a copy of my PST file and getting nowhere.  The solution for me was indeed to roll back my Office version.  I tried the 16.0.13901.20312 version first, but the error persisted.  Then I rolled back to 16.0.13801.20294, and poof, the error vanished.  Thank you very much for that suggestion and describing how accomplish the rollback.

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b

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I was experiencing this same problem, as others have described.  My machine updated last night, and today this problem is resolved.  Hope this helps others.

1.0.0.20

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The build number which fixed it would help a lot more.

(File, Office Account, About Outlook.)

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Sorry, Windows 10 build version: 19042.928 with Windows Feature Experience Pack 120.2212.551.0

Outlook version 2103 (Build 13901.20400) Current Channel.

 

1.0.0.20

1.0.0.20

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b

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Diane Poremsky, who provided details above, now confirms that latest updates are fixed:

Fixed: Could not read the Calendar

Last week I mentioned an error some users experienced when they switched between the Mail and Calendar modules, receiving a message “Could not read the Calendar”.

This bug is fixed. If you were affected by this bug and still have it, check for updates in Outlook then restart it. The fix is installed when you restart Outlook.

Exchange Messaging Outlook – April 22 2021 – Volume 26 Issue 11

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