Adjusting Sidebar width in OneNote

Hi @Cindy

Welcome to Microsoft Q&A forum 

To better understand your situation, may I clarify a few details: 

1.Are you using OneNote desktop app or OneNote for web version? 

2.Can you still see the double-headed arrow when hovering over the sidebar edge? 

3.Have there been any recent changes to your computer setup or environment that might affect how OneNote displays? 

4.Are you able to open your OneNote files by clicking on them, or does nothing happen when you try? 

I suggest you try some basic steps first: 

1.Reset OneNote Settings 

-Close OneNote completely. 

-Press Windows + R  

-Type regedit and press Enter to open the Registry Editor. 

-Navigate to: HKEY_CURRENT_USER\Software\Microsoft\Office<version>\OneNote 

(Replace <version> with the version number of Office installed (e.g., 16.0 for Office 2016). 

-Right-click on the OneNote folder and select Delete. 

-Restart OneNote 

2.Repair OneNote 

-Go to Settings > Apps > Installed Apps. 

-Find Microsoft 365 or OneNote. 

-Click the three dots next to it and choose Modify. 

-Select Online Repair or Quick Repair 

(For more information, please visit Repair an Office application - Microsoft Support ) 

3.Reinstall OneNote 

-Go to Settings > Apps > Installed Apps > Search for OneNote. 

-Click the three dots (⋯) > select Uninstall. 

-Confirm the action. 

-Open the Microsoft Store > Search for OneNote > Click Install. 

-Once installed, sign in with your Microsoft account to sync your notes 

(Reference: Install or reinstall OneNote for Windows - Microsoft Support ) 

The initial response may not fully address your needs, but it will help me better understand your situation. Thank you for your patience while we work through it 

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