Compatibility mode is suitable for older software with Windows 10 that fail to run normally. Thankfully, Microsoft Outlook is fully optimized for Windows 10, meaning Compatibility mode is not necessary. You might be wondering what happens when you switch on the Compatibility mode for Outlook. When you do this, your Outlook might have opening problems. For this reason, you should always turn off Compatibility mode for Outlook.

• We can fix the problem for you, or you can use the troubleshooting steps we're providing below to help resolve these startup issues.
• Starting Outlook in safe mode, which starts Outlook without add-ins loaded, can tell you if an add-in is the source of the problem.
• If this isn't what you were looking for, please respond and we can continue to troubleshoot until we find the right answer.
• A well-running Outlook will ensure that you enjoy the full benefits of this popular email program.
• Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
• Outlook opening problems are simple to deal with.
• However, if you encountered other issues like Outlook not responding, learn how to fix Outlook not responding here.

Older versions of Outlook may be out of support

Starting Outlook in safe mode, which starts Outlook without add-ins loaded, can tell you if an add-in is the source of the problem. Upgrade to Microsoft Edge to Fix Outlook and Office 365 Errors 2025 take advantage of the latest features, security updates, and technical support. Click the above link to have a quick download, then you can have Outlook errors fixed within minutes.

Why Won't Outlook Open?

Should you decide to remove a profile, back up the data files first. All offline cached content will be deleted when you choose Remove. For more information, see Introduction to Outlook Data Files (.pst and .ost). If you are trapped in a similar situation that my Outlook is not opening, you may feel disturbed about the problem. If Outlook is NOT able to start in safe mode, then try the next proposed solution below, entitled Create a new Outlook profile.

My Outlook won't open. It's an on-going problem. This time, though, when I shut down my laptop, and rebooted it, I am

You can run the Inbox Repair Tool (scanpst.exe) to scan your Outlook data files and repair errors. Are you having trouble starting Outlook or receiving "Cannot start Microsoft Outlook. Cannot open rebuild Outlook data file quickly the Outlook window" error messages? We can fix the problem for you, or you can use the troubleshooting steps we're providing below to help resolve these startup issues. Here's the deal, when Outlook manages to open, all the files you delete will automatically be recreated. It gets better because you also resolve all the Outlook opening issues. Please follow the steps specified in the below link.

Getting Started Is Easy

Running the /resetnavpane command removes all customizations to the navigation pane. Please go to Create an Outlook profile for steps on how to create a new Outlook profile, then continue with how to use a different profile. With the window with the Windows Update, you will see all the updates you need to make for your Microsoft Office.



If you would like for me to fix this issue using our Secure Remote Assistance then customer care can setup a new case for us. Occasionally, that profile can become corrupted. You can determine if it's corrupted by creating a new profile and changing which profile is used when Outlook starts. Use the classic Outlook startup troubleshooter to diagnose and fix several common classic Outlook for Windows issues for you. If you restart it successfully, it will show you that one or more add-ins are defective.

How to Avoid the "Outlook Won't Open" Problem?

If anyone finds a more permanent solution, I would appreciate it. It seems like something went wrong on Microsoft update and they might recall it or fix it, so we might need to wait untill that. If online repair didn't work, you Outlook sync help from FixTechGuide need to reinstall your Office application.