Every application has its benefits and downsides. The Microsoft Outlook application has several beneficial features that help manage emails and other tasks. But it is also prone to errors and issues that may prevent users from sending emails or accessing mailbox items.

One error that Outlook users can encounter is the error, “Can’t start Microsoft Outlook. Cannot open the Outlook window,” when opening the application. There are multiple reasons that cause this error in Outlook. In this article, we will discuss the reasons behind the error and methods to resolve it.

Reasons for ‘Cannot start Microsoft Outlook. Cannot open the Outlook window’ error

This Outlook error can occur due to one or more of the following reasons:

• Corrupt or damaged Outlook profile
• Incompatible or faulty Outlook add-ins
• Incorrect Navigation pane settings
• Corrupted or damaged Outlook data file (PST)
• Misconfigured Outlook startup settings
• Outdated Outlook version

Methods to resolve “Cannot start Microsoft Outlook. Cannot open the Outlook window” error

Outdated Outlook applications may develop some bugs or issues that can impact the application’s functionality.

First check if your Outlook is patched with the latest updates. If not, install the latest Outlook you can find. If this doesn’t cure the issue, try the troubleshooting methods below.

Method 1: Start Outlook in safe mode and disable add-ins

Faulty or incompatible add-ins may interfere with Outlook functionality, resulting in the “Cannot start Microsoft Outlook. Cannot open the Outlook window” error.

Run Outlook in Safe Mode to identify if a faulty add-in is causing the error. To open Outlook in safe mode:

• Press Windows + R to open the Run dialogue box.
• Type Outlook /safe and press Enter or click OK.

If the Outlook application opens without the error in Safe Mode, then the error is caused by a faulty add-in. Follow these steps to disable the add-ins:

• Go to File > Options > Add-ins.

• Under View and Manage Office Add-ins, select COM Add-ins from the Manage dropdown and then click Go.
• Uncheck all the add-ins and click OK.

• Click File > Exit to close Outlook.
• Start Outlook normally.

To find the faulty add-in, you can go to the COM add-ins window and enable one add-in at a time. Restart Outlook after enabling each add-in. When you find the problem, remove it permanently from Outlook.

Method 2: Create a new Outlook profile

The profile contains all your Outlook settings. If the profile gets corrupted or damaged, you may encounter the “Cannot start Microsoft Outlook. Cannot open the Outlook window” error. If your Outlook profile is corrupted, you can create a new profile and replace the corrupted one. To do so, follow the steps given below:

Open the Control Panel on your system. Click User Accounts and then click Mail.

• In the Mail Setup-Outlook window, select Show Profiles and then click Add.
• In the Profile Name field, enter the name you want to use for your new profile.
• On the Auto Account Setup window for the Add Account dialogue box, under E-mail Account, enter Your Name, E-mail Address, and Password, and then click Next.
• Click Finish.
• You can check the new profile under the General tab in the Mail dialogue box.
• Under When starting Microsoft Outlook, use this profile, select Prompt for a profile to be used, and then click OK.
• Restart Outlook.
• In the Choose Profile dialogue box, click on the dropdown list to choose the new profile. Click OK.

Method 3: Reset the navigation pane

Sometimes, changing the folder lists in the navigation pane in Outlook can cause issues when opening the application. You can revert changes to the navigation pane by resetting it. To do so, follow the following steps:

• Close the Outlook application (if open).
• Open the Run dialogue box (press Windows + R keys).
• Type Outlook.exe /resetnavpane and then press the Enter key or click OK.

Method 4: Repair the PST file

One of the major reasons behind the “Cannot start Microsoft Outlook. Cannot open the Outlook Window” error is corruption of the PST file. If a corrupt Outlook data (PST) file is preventing Outlook from starting, you can run the Inbox Repair Tool (Scanpst.exe) to scan and repair the corrupt PST file.

The Inbox Repair tool can fail, or it might display an error message saying, “Internal errors were found in this file. They must be repaired for this file to work correctly,” if the PST file is severely corrupted, encrypted, or it’s too large. In such a case, you can use an Outlook PST repair tool, like Stellar Repair for Outlook to repair the PST file.

It can repair encrypted, highly corrupted PST files without any size limits, with complete integrity. It can save the repaired file in a new PST file, which you can import into your Outlook profile. It also offers options to save the repaired PST file items in several other formats, like HTML, PDF, RTF, EML, and MSG.

Conclusion

If the Outlook data file (PST) is corrupted, you can repair it using the Inbox Repair Tool/SCANPST. If it fails to repair the PST file, then you can use an advanced Outlook repair tool, like Stellar Repair for Outlook. This tool can help you resolve corruption-related issues in the PST file and restore all the mailbox items.

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