Microsoft Outlook cache your data as you work. Typically, creating and storing cache helps Outlook to ramp up its operations. For instance, while you compose an email and specify a destination for it, the address of that particular destination gets cached to the memory as soon as you hit the Send button. The cached information automatically appears as a suggestion when you do a similar entry next time. Cache memory holds the data/key events most frequently entered by the user.

With each entry made by the user, the data gets accumulated into the cache, and over time it occupies a huge memory space in Outlook, which eventually affects the overall performance of the application. Fortunately, you can clear the cache storage whenever there is a performance issue due to the overloading of data. Moreover, clearing cache helps you get rid of auto-suggestions when you reinstall the application.

Cleaning Outlook's Cache

To clear the cache memory, first you need to find the location where the Outlook's cache data gets stored. Once you located the directory, you can easily clear the data by deleting the entries in the folder. To do the task more precisely, follow the instructions given below:

  1. Press Win + R to launch the Run Command dialog box.
  2. Type "%localappdata%\Microsoft\Outlook" and hit Enter.
  3. The above command will launch the cache data directory on your system.
  4. Double-click the RoamCache folder.
  5. Press Ctrl + A to select all cached data.
  6. Press Delete to clear the selected data.

The above 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 going through the following Steps.

How to clear individual entries in Outlook?

Sometimes users just want to get rid of an individual entry from the auto-suggestions thrown by the cache.

Outlook facilitates removing individual entries as you work with forms like emails and contacts. All you have to do is compose an email and remove the auto-suggestions that pops-out while typing the destination email address. To give you a better understanding of how to remove individual entries, we have described the method in Step wise manner stated below:

  1. Launch MS Outlook and click on New Mail button.
  2. In the New E-mail window, start typing the destination email address or the contact you wish to remove from the auto-suggestions.
  3. Select the required email or contact and click on the "x" button to remove the data from cache memory.
How to clear Autocomplete Cache data in Outlook?

Sometimes users share information very frequently which leads to too many auto-suggestions popping out while typing names. A short way to remove all the suggestions is to clear the auto-complete cache data at once.

  1. Launch Outlook and go to File > Options.
  2. In the Options window, select the Mail tab.
  3. Under Send messages section, uncheck the "Use Auto-Complete List to suggest names when typing in the To, Cc, and Bcc lines" check box.
  4. Click on the Empty Auto-Complete List button, and select Yes in the confirmation dialog box.
  5. Click OK to save the changes.

Regular performance issues can be sorted easily by clearing the cache memory, but Outlook also face issues like duplication of data. Many users have repeatedly reported that their Inbox still shows the mails that are either deleted or are moved to some other folder.

Duplicate data such as emails and contacts can consume unnecessary space in your Outlook mailbox and can slow down the application. Unfortunately, Outlook doesn't provide any direct measure to delete duplicate data from your mailbox. You have to look out for third-party resources to filter your duplicate items and remove them permanently from your mailbox.

Kernel for Outlook Duplicates Remover help users to remove and manage duplicate items from Outlook PST files. The tool locates duplicate data based on criteria like text, contact, subjects, Sender Email, Sender Name, and other relevant information. Moreover, it allows users to choose actions such as Delete, Mark as expire, Put flag, Copy, Move, etc. on duplicates. Also, Kernel for Outlook Duplicates Remover supports all versions of Outlook including 2019. Here is how the tool works:

  1. Launch Kernel for Outlook Duplicates Remover on your system. As soon as you launch the application, a dialog will pop on your screen asking you to create a new task. Click Yes.
  2. Enter a Task Name and Task Description, then click on Next to move further in the process.
  3. From the left-hand side panel, select the mailbox folders that contain the duplicate data. You can also select the root folder in the hierarchy. Click Next once you are done specifying the folders.
  4. Select the desired operation to be performed on the duplicate items. The operations available are Delete Permanently, Mark as expire, Move to deleted folder, and Put flag. You can also copy or move the duplicate items to a new folder by specifying the folder name next to the Copy and Move options. Click Next, once you have selected the desired operation.
  5. In the next window, select the properties that you want to use in order to compare the duplicates in your mailbox folder. For instance, you can use properties like Sender name, Receiver name(s), Internet header, Date and time of sending, and Attachment files. Click Next once you are done.
  6. The selected folders are scanned, and the specified operation is executed on the duplicate items. Click on the Save Report to save a report of the duplicates that are found out during the process. Click Finish.


Many Outlook users face performance issues because of piling up of Cache. They can fix the issue easily by clearing the Cache. But if they are facing duplicate issues in Outlook, they need to use a professional duplicate item removal tool.