How To Repair Outlook 365?

Ever since the rise of computers and the advancement of technology, Microsoft Office has been omnipresent. Many users prefer MS Outlook for their e-mail, and it offers great security features and a user-friendly interface. When you subscribe to Office 365, you will get to use Outlook.

Recently many complaints are coming from Windows 10 users related to Outlook 365. There are issues with the application crashing or not launching at all. In this article, we will see how to repair Outlook 365 and deal with such errors. Learn about various causes and solutions and check out the

Part 1: Symptoms

Windows 10 users don’t just face a single issue, and there are several errors that hinder users from using Outlook. It is a cause of stress for many users when these unnecessary and annoying users refrain from using the e-mail application.

If you experience any such problem, you will need to repair Outlook 365 at the earliest. Let us know about some of these symptoms and problems.

• Outlook 365 stuck at loading

It is one of the most common problems and arises when over time, a lot of notes, emails, calendars, attachments, etc., keep piling up and make PST files too large. When the size becomes, too much Outlook will become very slow and not work at all. If the application is stuck on loading, then you should know how to repair Microsoft Outlook 365.

• Outlook not responding or launching

Outlook crashed or not responding

Another common error you may see on clicking the Outlook icon is failed to launch, along with Outlook has stopped working. Some add-ins have bugs and can cause the application to crash. It also slows down the speed of the application by a lot and makes it impossible to use.

• Outlook PST files are corrupted

If a PST file on your Outlook is corrupted, the application will point it out to you as soon as you run Outlook. When there is a corrupt PST file on Outlook 365, the application will not run, and you won’t be able to access any other data.

• Sending spam mails

Another issue which you may come across is that your contacts got spam e-mails from your account even when you didn’t send anything to them. It can break your business partnerships and cause trouble by sending inappropriate emails to your contacts.

• Mails not displaying properly

Sometimes, people have Outlook installed on multiple devices and use it on different ones at different times. The settings on these applications and as a result, you may see a mail on some device and not on another one. Use Outlook 365 repair tool to tackle this issue.

Part 2: Possible Causes for Outlook 365 Problems

We have already read about the common issues and errors that Windows 10 users face. It is important to know the cause and reason behind these issues so that you will have help when you try to repair Office 365 Outlook. Check out some of the main reasons behind common Outlook errors.

  • The large size of PST files is one of the top reasons behind errors and bad running of Outlook. When PST size becomes very large, Outlook will start showing problems, and you will have to clear some space by deleting unnecessary stuff. Archiving e-mails and other stuff is another easy and effective way to tackle the issue of heavy PST file size.
  • Third-party plug-ins and add-ons are another top menace to Microsoft Outlook. Some tools have bugs that affect the application’s performance. Try to open Outlook in safe mode without any plug-ins and see if it working nicely. Remove all faulty plug-ins and improve Outlook. If this is not the issue, then you will require a Microsoft Office 365 Outlook repair tool.
  • Faulty and corrupt PST files are a major reason for Outlook errors. All data of the application is stored in PST files, and any corrupt data is bound to hinder the application. You can use the built-in repair tool to fix such files, or you should know how to repair Office 365 Outlook PST file.
  • Using Outlook on multiple devices is another action that asks for trouble. You will not be able to see all e-mails and use every feature of the application properly on some devices. Check every device and find the one which shows every mail and other data. Copy its PST file and paste it on your primary device. An Outlook 365 inbox repair tool can help out in such situations.
  • A hacker can have access to your computer, or there is a virus or some other malware in your device that affects the system. Someone from outside can access your e-mail account and send unwanted spam emails. He can even interfere with your data and either steal or delete it. Log out from every device and change your password in case you experience anything related to this.
  • 6.Outdated and slow devices will also face some problems while running Outlook 365. Some older operating systems do not have advanced security features and have slow processors. For those who use older versions like Windows 7, it is necessary to know how to repair outlook 365 in Windows 7. It is a bit different as compared to Windows 10, so you must know what to do exactly.

Part 3: How to Repair OST File in Outlook 365?

Microsoft provides offline storage to users for the storage of mail data and other information. OST files carry a copy of the data present on the Exchange server. If you aren’t connected to Exchange, you can still access these files through OST files.

OST files do not change the original data and just make a copy of the actual thing. Just like PST, OST files can also be corrupted and cause performance and other issues. If you want the ship to sail smoothly, you have to know about Outlook 365 OST repair. Here are the top two ways to repair an OST file.

Method 1: Using scanost.exe

Using scanost.exe

It is a reliable tool that works smoothly to open and view damaged and corrupted OST files and repair them effortlessly in a short time period. It checks the integrity of the files first and is also named Integrity check tool.

You can use it to scan and compare data with the one available on Exchange and find any conflict, and maintain harmony between the client and the server.

Method 2: Using Kernel OST Viewe

Kernel OST Viewer is one of the best Outlook repair tool Office 365, available for free. One can easily use the tool to view and repair OST files. Even if some files were password-protected, this tool is capable to open and repair them. You just have to search and select the required OST file.

Kernel OST Viewer analyzes OST file data repair and works with all versions of Outlook 365. If you are wondering how to repair OST file Outlook 365, then follow these steps.

Step 1: Launch Kernel OST Viewer on your PC and search for then open the concerned OST file. You may choose one or more than one file.

 Browse and select OST file

Step 2: Go through Process Information and proceed to view any folder from the list and check its content.

 Read process information

Step 3: Open Task Panel and select one of the various types of reports to see a File Analysis Report. Choose any folder you want and click Analyze.

Select File Analysis Type

Step 4: A window will appear when the search finishes, and you have to press OK. Check out file analysis reports based on various parameters. Kernel OST Viewer is a top tool in the market designed to repair OST files. Make sure to take a look at this wonderful product.

 Check analysis report and save OST file

Part 4: How to Repair PST File in Outlook 365?

PST files are the main storage areas for all data of Outlook 365. Sometimes, these files get corrupted or don’t open because of other issues. As a result, Outlook also stops working, and you need to do something to repair PST files.

Stellar File Recovery tool can be used to repair PST file Outlook 365 in an efficient manner. All types of mail, calendar, notes, lists, attachments, etc., in a PST file can be recovered through this tool. It scans files deeply to recover data and can repair PST files as large as 2 GB in size. You can preview data before restoring it, and e-mails can be directly restored after preview.

This tool can also be used to open and restore data from password-protected PST files. Here are the steps for repairing PST files through the Stellar Outlook Repair Tool.

Step 1: Download and install the Stellar Recovery Tool on your device. Launch the software, and it will automatically search for and find all PST files for scan and repair.

Launch Stellar recovery tool to scan OST files

Step 2: Click Choose Location and browse manually for the PST file if the tool is not able to find the file through its search in default locations.

Make a custom search for PST files

Step 3: The tool will start scanning the PST file and repair it to retrieve data. You will see a Repair Complete prompt and have to click OK.

 Click OK after repair is complete

Step 4: You can preview all data inside the repaired PST file and see its contents. Click on Save Repaired File after this.

Preview restored files

Step 5: When the Save As window appears, make sure you use the PST extension for the file. Browse for the location where you want to save the restored file and click OK to finish the process.

Save the restored file


Microsoft Outlook is one widely-used e-mail application by Office users. All data is stored in PST and OST files. When there is an issue with these files, Outlook won’t run properly. You must know how to repair Microsoft Outlook 365 if you want to resolve these issues.

In the above article, we read about various issues experienced by Outlook users and ways to resolve them. Stellar File Recovery Tool is one of the best products if you want to repair PST files and recover all lost files and data. Install the tool now and make sure Outlook works fine all the time.