A technician receives a call from a user who is unable to open Outlook.

Operating system updates can sometimes cause compatibility issues with some applications, such as Outlook, that may prevent them from opening or working properly. This can happen if the update changes some system files or settings that Outlook relies on, or if the update conflicts with some Outlook add-ins or extensions. To fix this, the technician can try some of these troubleshooting steps:

Start Outlook in safe mode and disable add-ins. Safe mode is a way of starting Outlook without any add-ins or extensions that may interfere with its functionality. To start Outlook in safe mode, press and hold the Ctrl key while clicking on the Outlook icon. You should see a message asking if you want to start Outlook in safe mode. Click Yes. If Outlook works fine in safe mode, it means one of the add-ins is causing the problem. To disable add-ins, go to File > Options > Add-ins. In the Manage drop-down list, select COM Add-ins and click Go. Uncheck any add-ins that you don’t need and click OK. Restart Outlook normally and check if the issue is resolved4.

Create a new Outlook profile. A profile is a set of settings and information that Outlook uses to manage your email accounts and data. Sometimes, a profile can get corrupted or damaged and cause Outlook to malfunction. To create a new profile, go to Control Panel > Mail > Show Profiles. Click Add and follow the instructions to set up a new profile with your email account. Make sure to select the option to use the new profile as the default one. Restart Outlook and check if the issue is resolved5.

Repair your Outlook data files. Data files are files that store your email messages, contacts, calendar events, and other items on your computer. Sometimes, data files can get corrupted or damaged and cause Outlook to malfunction. To repair your data files, you can use a tool called scanpst.exe, which is located in the same folder where Outlook is installed (usually C:\Program Files\Microsoft Office\root\Office16). To use scanpst.exe, close Outlook and locate the tool in the folder. Double-click on it and browse to the location of your data file (usually C:\Users\username\AppData\Local\Microsoft\Outlook). Select the file and click Start to begin the scanning and repairing process. When it’s done, restart Outlook and check if the issue is resolved.

Run the /resetnavpane command. The navigation pane is the panel on the left side of Outlook that shows your folders and accounts. Sometimes, the navigation pane can get corrupted or damaged and cause Outlook to malfunction. To reset the navigation pane, press Windows key + R to open the Run dialog box, or open the Command Prompt. Type outlook.exe /resetnavpane and hit Enter. This will clear and regenerate the navigation pane settings for Outlook. Restart Outlook and check if the issue is resolved.