Keep Getting "Outlook closed while you had items open. Reopen items from last session?" Even Though It's Not True

These are my instructions (which are also on page 4 of this thread).

Just so everyone knows:

The procedure to revert to a prior version (any prior version) applies to Microsoft 365, and the C2R versions of 2013, 2016, and 2019 of Outlook. The Outlook versions must be Click-To-Run and will not work for other versions.

That command tells the Client to Run app file on these system to upgrade to the version listed in the command.

To help understand this process here are my instructions oh how to revert to a prior version written in more detail.

Undo an Outlook Update

Note:  This applies to only C2R versions of Outlook.  This includes Microsoft 365 and the C2R versions of 2013, 2016, and 2019.  To see if you have the C2R version: open Outlook, select File > Office Account. Look for C2R or Click-to-Run after the version and build number under About Outlook.

What

A command in an Administrator’s Command window and an Internet connection can cause Outlook to “update” to the build number indicated in the command.  Using the prior version’s build number reverts Outlook to the prior version and “undoes” the update.   

Why

When an update to Outlook (which installs silently) causes problems, you can undo the update and revert to the version you had before the update occurred as a way to get rid of the problem.  Reverting to a prior version and stopping updates avoids the problems and gives Microsoft time to fix the update bug.  After you find out the update has been fixed, then you can resume updates problem free (hopefully).

How

Step 1 - Disable Outlook Updates

• Open Outlook
• Select File > Office Account
• Click dropdown arrow by Update Options
• Select Disable Updates.  This will cause an UAC box to open to authorize this change.  Click Yes to allow the change in settings.

Step 2 - Find Build Number to Revert To

• The command directs Outlook to change its files to match those found in the build number indicated in the command.  In order to revert to the prior version you need the build number for that prior version.  Here’s how to find that build number for the prior version:
• Open Outlook
• Select File > Office Account
• Under About Outlook note your current version and build number
• Click the dropdown arrow for Update Options and select View Updates.  This opens your default browser to a Microsoft Release Notes page with a list of versions for your Outlook.
• Click the version list just below the version you currently have.  The version number is a link to specific details of that version including the build number for that version.
• Make sure you have the right version and if the same version number is listed twice, select the last one released.  To make sure I get the build number correct, I highlight and copy just the number as well as write it down.

Step 3 - Revert to Prior Version

• You must have your PC connected to the Internet.  Close Outlook.
• Open an Administrator Command window by opening a Run box (WinKey + R), enter cmd, press the Ctrl + Shift + Enter keys at the same time, and click Yes to the UAC query box that opens.
• At the prompt enter the following command and press the Enter key: *CD %programfiles%\Common Files\Microsoft Shared\ClickToRun*
• The above command is suitable for copy and paste.  Note the space between CD and %.  This command will change the prompt location to the folder where the OfficeC2RClient.exe application file is kept.  The above command changes the prompt location to the default location on all the versions stated above except 2013 C2R, whose default location is in a different folder.  Search for the folder that contains the OfficeC2RClient.exe file and adjust the command above to change the prompt location to that folder.
• With the prompt location at the folder that the OfficeC2RClient.exe file is located in, enter the following command: OfficeC2RClient.exe /update user updatetoversion=16.0.build number
• The above command is Not suitable for copy and paste.  The build number must be replaced by the actual build number for the version you want.   Notice the 16.0. before the build number.  This is the Office group number which is 16.0 for 365, 2016, and 2019.  For 2013 the group number is 15.0.  Note the period between the group number and the build number.  Example of the command for Outlook 2019 C2R to revert from version 2306 to version 2305 (Build 16501.20210): OfficeC2RClient.exe /update user updatetoversion=16.0.16501.20210
• After pressing the Enter for your command various windows will open as the OfficeC2RClient app gets the files from Microsoft and performs the version placement requested.
• When finished the prompt will return to the same prompt location awaiting your next command.
• Close the Command window.
• Open Outlook and check the version/build in Office Account and you will see the version build you requested.
• You will also see that whatever the last update did, reverting to a prior version has undone what it did.

My testing showed that the update to version 2306 build 16529.20154 that was released June 26, 2023 removed the Startup Options on the General tab of Outlook (which has Ask to open items as the default setting, which causes the popup questions). To prove this I rolled back to the prior version 2305 build 16501.20210, which restored the 3 Start up options on that General tab. After the upgrade to version 2306 I did not get the popup box asking to reopen items, but I had that option set to Never reopen items selected before the upgrade occurred. I checked and that Registry key is set to the value of 1 which is for the Never option (0 is for Ask and 2 is for Always open items). Changing that key value to 1 should work.

So...how do I do this?

My contact in support just let me know that he repro'd it in both Outlook 2019 and 2021 and submitted a bug report on it ...

Hi Diane Poremsky:

There's speculation in CSG-08's 04-Jul-2023 thread My Outlook 2016 "Start Up Options menu" has no drop down submenu that this problem could be connected to the appearance of the "Try the new Outlook" switch in perpetual editions of MS Outlook 2016 / 2019 / 2021 - see garrybock's 19-Jul-2023 post <here> on page 5 of that thread.

I'm not sure how it happened but the experimental preview of the MS Outlook for Windows PWA (progressive web app) was installed on my system a few months ago - see the images I posted in my 07-May-2023 thread "New" Outlook for Windows UWP App (Preview) Installed Without Permission. I never launched the "new" Outlook app and tried to remove the last traces of it from my system with O&O AppBuster, but perhaps the installation was enough to do permanent damage to my MS Outlook 2019 registry entries and settings.

According to the 04-Apr-2023 Microsoft 365 Insider blog entry Starting to Support Third-party Accounts in New Outlook for Windows if you turn on that "Try the new Outlook" switch to test the preview of the "new" Outlook PWA "You can switch back to your previous Outlook experience . Just slide the toggle off and it will automatically open your previous version with no data or email loss." That might be true for M365 but perhaps that isn't the case for perpetual editions of MS Outlook 2016 / 2019 / 2021 Click-to-Run.

Just to recap, the section at File | Options | General | Start Up Options in my Outlook 2019 settings is now blank (i.e., there is a section header but no check boxes or dropdown lists), there is no section named Cloud Storage Options at File | Options | General, I have no registry entry for ReopenWindowsOption at HKEY_CURRENT_USER | SOFTWARE | Microsoft | Office | 16.0 | Outlook | Preferences (for now, I've decided not to re-create this registry entry manually), and I am still seeing the occasional "Outlook closed while you had items open. Reopen those items from your last session?” prompt when I start Outlook 2019.

Dell Inspiron 5584 * 64-bit Win 10 Pro v22H2 build 19045.3208 * Firefox v115.0.2 * Microsoft Defender v4.18.23050.5-1.1.23060.1005 * Malwarebytes Premium v4.5.33.272-1.0.2069 * Macrium Reflect Free v8.0.7279 * Microsoft Office 2019 Home and Business 2019 Version 2306 / Build 16529.20182 C2R

Hi, Diane:

As an FYI, there was a Microsoft 365 (Office) update pushed out via the Microsoft Store yesterday. The update was installed on my computer, and the "Outlook closed while you had items open" message disappeared for about 24 hours. Today, the message has REAPPEARED.

Whew...this is annoying...

John L.

Note: Running fully licensed Microsoft Office Home and Business 2021.