I very recently started having Outlook crash due to ucrtbase DLL dying. Outlook even crashes in SAFE mode

Question

I'm running Windows 11 with the latest build. I'm running Office 365 with classic Outlook. The faulting details are below:

Faulting application name: OUTLOOK.EXE, version: 16.0.17830.20138, time stamp: 0x66aaad8c

Faulting module name: ucrtbase.dll, version: 10.0.22621.3593, time stamp: 0x10c46e71

Exception code: 0xc0000005

Fault offset: 0x000000000005137c

Faulting process id: 0x0x5A00

Faulting application start time: 0x0x1DAE741D3515015

Faulting application path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE

This just started happening!

Answer 1

John,

Were you able to get past this? I watched your video, and I found the fault bucket from your event viewer logs.

Fault Bucket 1620625936954482602

When I look at that bucket in our internal tool it shows it defined as: invalid_pointer_read_c0000005_outlook.exe!hrcreaterulefromblob.

This is pretty close to what I see with the one support case. It appears this is caused by bad rules and most likely coming from the service. If you go to Outlook Web Access for that account, can you delete all the rules there if any, https://outlook.office.com/mail/options/mail/rules

These steps should mitigate it unless Outlook somehow cannot remove the bad server rule.

1. Clean rules (reference, Command-line switches for Microsoft Office products - Microsoft Support)

Right click the Window Start button and click Run

In the Run box paste: Outlook.exe /cleanrules

Click OK

2. New Outlook profile, if necessary, Create an Outlook profile - Microsoft Support

Answer 2

To try to mitigate this issue do an Online Repair of Office, see instructions here. In some cases, graphics drivers can cause a crash like this so check to make sure the drivers for your device are up to date, Update Windows - Microsoft Support.

If you have an option to submit an In App ticket click Help, Contact Support from Outlook. An issue like this will likely require an escalation engineer to review a hang dump to determine root cause. Is there any specific task you are doing in Outlook when the issue happens?

To confirm if the issue started in this build 17830.20138 you could revert to the prior build. If you are using M365 Current Channel you could revert by doing the following:

1. Open a Command Prompt (run as Administrator)
2. Type/paste the two commands and press Enter after each

cd %programfiles%\Common Files\Microsoft Shared\ClickToRun

officec2rclient.exe /update user updatetoversion=16.0.17726.20160

I pulled the build from Update history for Microsoft 365 Apps (listed by date) - Office release notes | Microsoft Learn.

Answer 3

Hi Gabriel, I followed these steps and NOTHING has worked.

1: Made sure I have all the Windows updates (win 11 Pro - Ver 23H2; OS Build 22631.3958)

2: I reverted back to the Build 16.0.17726.20160 -- Outlook still crashes immediately -- even in SAFE mode

3: I changed to the ClickToRun directory and ran the updatetoversion you listed -- still crashing

4: Finally, I completely DELETED Office 365 and rebooted.

5: I re-installed Office 365 -- rebooted again

6: Started Outlook -- it still crashed immediately.

Really need help. I will try opening a ticket with Outlook support, but I cannot keep Outlook up long enough to submit a ticket. Any other ideas, I'm wide open for suggestions!

Answer 4

Try creating a new Outlook Profile. Hold down the Shift key when starting Outlook, on the Profile Picker dialog click Options, check Prompt for profile to be used, then click New and proceed through the prompts. Official guidance, Create an Outlook profile - Microsoft Support.

I would try reverting to a much older build to make sure no recent Office change is causing it. I pulled this build below from December 12th, Update history for Microsoft 365 Apps (listed by date) - Office release notes | Microsoft Learn.

1. Open a Command Prompt (run as Administrator)
2. Type/paste the two commands and press Enter after each

cd %programfiles%\Common Files\Microsoft Shared\ClickToRun

officec2rclient.exe /update user updatetoversion=16.0.17029.20108

Answer 5

In case it is an add-in causing the issue, do the following:

Right click the Window Start button and click Run

In the Run box paste: outlook.exe /safe:3

Click OK

Command-line switches for Microsoft Office products - Microsoft Support