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Written By Evren Cole
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Updated on July 23rd, 2025
Summary: MS Outlook stores its data in a Personal Storage Table (PST), and if you use Outlook for a very long period of time then it tends to reach the maximum limit. Therefore, you need to make more space to work with Outlook otherwise you won’t be able to use Outlook. So in this article, we will explain various ways to reduce Outlook data file size if your Outlook data file has reached maximum size. Additionally, we will also provide a quick and risk-free solution using the Outlook PST Repair Tool. Download Now Purchase Now
Even though a Unicode PST file can expand up to 50 GB in any Outlook version. However, the recommended maximum size limit for a PST file is 20 GB to maintain Outlook performance and avoid PST file corruption as a result of oversizing. But don’t worry, here in this blog, we will provide you with several solutions that can help you reduce Outlook data file size. So let’s move on to the next part.
MS Outlook provides a few options to solve the “Outlook PST reached maximum size” error. So let’s explore all of them to find the perfect quick fix that goes with your requirement.
By using this option in Outlook you can save the older mail items in a new local PST file with attachments and that can significantly reduce the mailbox and PST file size. So follow the steps below.
If you want to completely clean your mailbox items, then you can convert all your data into a local PST file with the help of the Import/Export option. After doing that you can delete all the data from Outlook to clean up the space.
The best way to fix the “Outlook reached maximum size” error is to compress it, and you can easily do it with MS Outlook. Follow the steps below to do so.
You can also use the professional PST Compact Tool to compress the size of PST files. It is a quick and risk-free tool that compacts the PST files without any data alteration.
If you have enabled shared folder synchronization, then you can experience an increase in the size of the OST file, which can lead to Outlook performance issues. That is why follow the mentioned below steps to disable it to fix the Outlook data file has reached maximum size.
Having a huge pile of attachments can lead to an oversize PST file. So to avoid this problem, you can export all your attachments to a local folder, external drive, or cloud. After that, delete all of them from the email, and that can surely reduce the size of your PST file. To do so, follow the steps below.
These are all the solutions that you can use to reduce the size of Outlook data files to resolve the error. They all are reliable and you can safely use them as per your requirement. However, this error occurs sometimes due to corrupt PST files, so you can use Outlook PST Repair Tool to restore them in perfectly healthy condition. This is advanced software that allows users to recover data from corrupt PST files and restore them into new PST, EML, DBX, MSG, and MBOX without any size limitation.
This blog consists of reliable solutions to fix the error “Outlook data file reached maximum size”. They all are working on solutions that are easily formable with security. So choose the method that is associated with providing a solution for your problem. Well, on the other hand, if your Outlook data file is corrupted, then you can try a professional solution to repair them with 100% proficiency.
A: This error means your Outlook PST (Personal Storage Table) or OST (Offline Storage Table) file has grown too large and reached its storage limit, preventing Outlook from adding new emails, calendar entries, or other data.
A: Outlook may stop sending/receiving emails, become unstable, or crash. Data loss is also possible if the file becomes corrupted.
A: No, reinstalling Outlook does not reduce the size of your data file. You must reduce or archive data manually or increase the file size limit.
About The Author:
Evren Cole is an expert in Email and Data Management. She has a strong passion for technology and entrepreneurship. In her free time, she enjoys football, music, and reading books.
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