Excel 2609 (Build 20430.20092) crashes when opening files from OneDrive – Rtc.dll 0xc0000005

Hi @BAE DONGUK

Based on the information provided, this appears to be a regression introduced in Excel Version 2609 (Build 20430.20092) rather than a local configuration issue.

The key indicator is that:

• The crash occurs consistently when opening files from OneDrive.
• The same files open successfully when copied to a local folder.
• Standard remediation steps (Office repair, OneDrive reset, relinking the account, disabling add-ins, and rebooting) did not resolve the issue.
• Rolling back from Version 2609 (Build 20430.20092) to Version 2608 (Build 20326.20158) immediately restored normal functionality.

The Event Viewer entry showing Rtc.dll as the faulting module with exception code 0xc0000005 further suggests that the failure is occurring within Office components included in that specific build.

At the time of writing, I am not aware of a publicly documented known issue specifically matching this exact scenario. However, the rollback test provides strong evidence of a build-specific regression.

I recommend:

1. Remaining on Version 2608 until a newer Current Channel build becomes available.
2. Monitoring the Microsoft 365 Apps release notes for fixes related to Excel, OneDrive integration, or application crashes.
3. Opening a support case with Microsoft and providing the Event Viewer logs and rollback results, as these details can help Microsoft confirm and investigate the regression.

If other users can reproduce the same behavior on Build 20430.20092, it would help determine whether this is a broader product issue rather than an isolated environment problem.

If this issue matches your experience, please consider upvoting this question. Additional votes can help increase visibility and assist Microsoft in determining the impact of the problem and prioritizing investigation.

**If you have encountered the same behavior, please share your Microsoft 365 Apps version, update channel, and any relevant Event Viewer details to help with troubleshooting and root cause analysis.**Based on the information provided, this appears to be a regression introduced in Excel Version 2609 (Build 20430.20092) rather than a local configuration issue.

The key indicator is that:

• The crash occurs consistently when opening files from OneDrive.
• The same files open successfully when copied to a local folder.
• Standard remediation steps (Office repair, OneDrive reset, relinking the account, disabling add-ins, and rebooting) did not resolve the issue.
• Rolling back from Version 2609 (Build 20430.20092) to Version 2608 (Build 20326.20158) immediately restored normal functionality.

The Event Viewer entry showing Rtc.dll as the faulting module with exception code 0xc0000005 further suggests that the failure is occurring within Office components included in that specific build.

At the time of writing, I am not aware of a publicly documented known issue specifically matching this exact scenario. However, the rollback test provides strong evidence of a build-specific regression.

I recommend:

1. Remaining on Version 2608 until a newer Current Channel build becomes available.
2. Monitoring the Microsoft 365 Apps release notes for fixes related to Excel, OneDrive integration, or application crashes.
3. Opening a support case with Microsoft and providing the Event Viewer logs and rollback results, as these details can help Microsoft confirm and investigate the regression.

If other users can reproduce the same behavior on Build 20430.20092, it would help determine whether this is a broader product issue rather than an isolated environment problem.

If this issue matches your experience, please consider upvoting this question. Additional votes can help increase visibility and assist Microsoft in determining the impact of the problem and prioritizing investigation.

If you have encountered the same behavior, please share your Microsoft 365 Apps version, update channel, and any relevant Event Viewer details to help with troubleshooting and root cause analysis.

Hi BAE DONGUK,

Your testing strongly suggests that the crash is build-specific rather than caused by the workbook, OneDrive synchronization, or an Excel add-in. In particular, the same cloud files work locally, and the problem disappears after reverting from Build 20430.20092 to Build 20326.20158.

The release notes for Build 20430.20092 mention a fix for Excel becoming unresponsive during closing, but they do not document a OneDrive opening crash or provide a planned fix build for this exception.

As an alternative to remaining on Version 2608, could you test whether temporarily disabling AutoSave prevents the crash:

1. Start Excel without opening a workbook.
2. Go to File > Options > Save.
3. Clear AutoSave OneDrive and SharePoint Online files by default in Excel.
4. Close Excel completely, reopen it, and test a OneDrive workbook.

This test is relevant because AutoSave and real-time co-authoring are activated for workbooks stored in OneDrive or SharePoint. Turning off AutoSave stops real-time synchronization, although the workbook must then be saved manually.

If Excel opens successfully with AutoSave disabled, that would further narrow the problem to the cloud collaboration or real-time synchronization path used by this build. It would provide a potentially less disruptive workaround than downgrading Office. However, it is only a diagnostic workaround, and users should save frequently because real-time co-authoring and automatic saving will be unavailable.

I would avoid manually deleting the OfficeFileCache folder as a general test. Please note that manually removing cache artifacts can itself cause Office documents to crash when opened from OneDrive or SharePoint and may create upload or recovery problems.

Since you are using Microsoft 365 Apps for business, the best next step is for your Microsoft 365 administrator to open a support request and include:

• The Event Viewer entry and fault offset
• EXCEL.EXE and Rtc.dll version 16.0.20430.20092
• Confirmation that several OneDrive workbooks are affected
• Confirmation that local copies open normally
• Confirmation that Version 2608 resolves the crash
• Whether disabling AutoSave changes the behavior

Office diagnostic logs can provide Microsoft with additional information about the processes and components involved in an application failure.

In the meantime, the safest practical options are to remain temporarily on Version 2608, test with AutoSave disabled, use Excel for the web, or work from a local copy while ensuring changes are synchronized carefully.

For reference

• Fixes or workarounds for recent issues in Excel for Windows
• Release Notes for Office Current Channel (Preview)
• What you should know about AutoSave
• About coauthoring in Excel
• Managing Office document cache size

I hope the information I shared earlier was somewhat helpful in addressing your issue. If you have any further questions or updates, please don’t hesitate to share.

Kind regards,

Microsoft released Version 2609, Build 20430.20182 on Oct 13th. Try updating to that. The issue could be addressed by this release.