Microsoft Outlook has a feature that caches your data as you work. This caching process is instrumental in optimizing Outlook's performance. For example, when you compose an email and designate a recipient, the recipient's address is stored in the cache memory as soon as you click the 'Send' button. This cached information subsequently appears as a suggestion when you enter similar data in the future. The cache memory retains the most frequently used data and key events entered by the user.

Each time a user enters data, it accumulates in the cache, gradually occupying a significant amount of memory space within Outlook. This accumulation can eventually have a detrimental impact on the application's overall performance. Thankfully, users have the option to clear the cache storage when performance issues arise due to data overload. Furthermore, clearing the cache eliminates auto-suggestions, which can be useful when reinstalling the application.

Cleaning Outlook's Cache

To clear the cache memory, you must first identify the location where Outlook's cache data is stored. Once you've located the directory, you can effectively clear the data by deleting the entries within the folder. For a more precise approach, please follow the instructions provided 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. Clear the cache memory
  5. Press Ctrl + A to select all cached data.
  6. Press Delete to clear the selected data.

The method outlined above clears the entire cache history of your Outlook application. However, if you wish to clear individual entries or specifically target the Autocomplete cache data, you can accomplish this manually by following the steps below:

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 provides a convenient method for removing individual entries as you interact with forms such as emails and contacts. Simply compose an email and delete the auto-suggestions that appear when you type the recipient's email address. To provide a clearer understanding of how to remove individual entries, we've outlined the steps in a systematic manner below:

  1. Launch MS Outlook and click on New Mail button. Launch MS Outlook
  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. Select the required email
How to clear Autocomplete Cache data in Outlook?

At times, users may share information so frequently that it results in an excessive number of auto-suggestions appearing while typing names. To quickly eliminate all these suggestions, you can opt to clear the entire 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. Click on the Empty Auto-Complete List button
  5. Click OK to save the changes.

While clearing the cache memory can effectively address common performance issues, Outlook may still encounter other issues, such as data duplication. Many users have reported experiencing situations where their Inbox continues to display emails that have either been deleted or moved to different folders.

Duplicate data, including emails and contacts, can occupy needless space in your Outlook mailbox and potentially hinder the application's performance. Regrettably, Outlook lacks a built-in feature for directly removing duplicate data from your mailbox. To address this issue, you must seek third-party solutions that can assist in identifying and permanently removing duplicate items from your mailbox.

Kernel for Outlook Duplicates Remover is a utility designed to assist users in efficiently removing and managing duplicate items from Outlook PST files. This tool employs various criteria such as text, contact information, subjects, sender email, sender name, and other relevant data to locate duplicate entries. Furthermore, it offers users the flexibility to select actions like deletion, marking as expired, flagging, copying, moving, and more for handling duplicate items. Notably, Kernel for Outlook Duplicates Remover is compatible with all versions of Outlook, including Outlook 2019. Below, we outline how the tool operates:

  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. Launch Kernel for Outlook Duplicates Remover
  2. Enter a Task Name and Task Description, then click on Next to move further in the process. Enter a Task Name and Task Description
  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. select the mailbox 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. Select the desired operation to be performed
  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. Select the properties that you want to use
  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. Click on the Save Report


Numerous Outlook users encounter performance problems due to the accumulation of cache data, which can be resolved by clearing the cache. However, when dealing with duplicate issues in Outlook, it's advisable to utilize a professional duplicate item removal tool to effectively address the problem.