How to Clear Outlook Cache Without Losing Emails?
Written By: Sarthak Poswal 
Updated On September 24, 2026 Written By: Sarthak Poswal Updated On September 24, 2026 Quick Answer: To clear Outlook cache, go to the RoamCache folder and delete the contents inside. Moreover, to delete the locally cached copy of mailbox data, delete the OST file associated with your Outlook account.
When the user starts experiencing slow Outlook, delays in sending/receiving emails, email sync failures, and more, clearing the accumulated huge Outlook cache can help.
In this guide, we will discuss the methods to clear Outlook cache from classic Outlook and New Outlook without deleting any emails. But before that, let's see what problems you can fix by removing the cache in Outlook.
Outlook stores cache in three different ways, including the cache files in RoamCache folder, the AutoComplete data, and the OST file for those using the Cached Exchange Mode in Outlook. A few common Outlook problems that require you to clear Outlook cache are:
Yes. Removing cache from Outlook is safe and is no threat to your emails and other mailbox items. This process is different than clearing the Outlook mailbox. Whether you are deleting the cache contents from the local Outlook directory or wiping out the Outlook autocomplete cache data, all your emails stay as they are without any change.
However, there is one data loss possibility to look out for when deleting the OST file. Generally, deleting and creating a new OST file is considered safe because your actual data is stored on the server. But this rule is not applicable to an email that fails to sync with the server and is only present in the local folder. Such emails will be lost permanently.
Based on the type of cache you want to delete; the method is different. In this section, we will see the steps to delete Outlook cache from RoamCache folder, Autocomplete cache data, and the OST file containing the cached emails in classic Outlook.
To delete the cache data from the RoamCache folder, follow these steps:
This method clears the complete cache history of your Outlook application. In case you want to clear individual entries or the Autocomplete cache data, you can do it manually by following the method below.
You can also clear Outlook cache by removing the email address that Outlook suggests when entering the receiver’s email address with the following steps:
In case you do not want to delete the complete list of autosuggestions, you can delete the autosuggestions one by one. For this, when Outlook suggests email addresses when typing in the To, CC, and BCC fields, click the cross icon for the email address that you want to delete.
If your goal is to clear up the cached mailbox data, including emails, attachments, calendar, contacts, notes, tasks, and folders, you must delete the OST file. To do this, press Win key + R, type “%localappdata%\Microsoft\Outlook” and press Enter.
From the folder, find and delete the OST file that is associated with your Outlook account. However, before deleting the OST file, make sure all the emails in your Outlook are correctly synchronized with the email server. For this, you can simply log in to Outlook on the Web and verify if all the emails are visible in both the desktop application and on the web.
New Outlook uses a different approach for creating and storing cache data. Since this Outlook version works on a web-based architecture, you have to use Microsoft Edge to clear its cache. Steps to delete cache in New Outlook are:
Most users look for how to clear the Outlook cache when they start experiencing issues in Outlook. However, in addition to deleting Outlook cache, there are other tips to help keep Outlook error-free, like:
Monitor mailbox size: Microsoft recommends maintaining the size of OST and PST files under 50 GB. An oversized Outlook data file is more likely to face severe performance issues, header corruption, and file indexing issues.
Update Outlook: Latest updates are important to avoid bugs and online threats. Moreover, an outdated Outlook often deals with compatibility issues, leading to performance drops.
Disable unnecessary Outlook add-ins: Add-ins add extra functionality to Outlook. But an incompatible add-in may create issues. Remove or disable any add-in that causes Outlook to freeze, or if you are no longer using it.
Remove duplicate items: Finding and removing duplicate items is a necessary step for keeping the OST/PST file under controlled size. However, manually finding and deleting a copy of an email is time consuming. A faster way is to use an Outlook duplicate file remover tool, like Kernel for Outlook Duplicate Remover. The tool allows you to search and find duplicate items by From, To, date, attachments, subject, text, and internet header.
Many Outlook users face performance issues because of piling up of cache data. Clear Outlook cache to fix such issues using the above-discussed methods. Moreover, an oversized OST or PST file can also slow down Outlook. Try to manage Outlook mailbox size by deleting obsolete emails or removing duplicate items using tools like Kernel for Outlook Duplicate Remover.
Ans: Outlook stores cache data to deliver faster search results, provides auto-completion of email addresses when composing a new email, and aids in smooth Outlook performance.
Ans: Classic Outlook stores the cache data in the RoamCache folder in the directory where the OST file is stored. In New Outlook, the cache data is stored on the Microsoft Edge browser.
Ans: Yes, you can delete Outlook cache without any risks. Clearing cache does not delete any data from your email server.
Ans: The cached mailbox data is stored in the OST file associated with the Outlook account. To delete the OST file, go to the location where the OST file is stored and delete it.