OST file size limit, the problems related to the data and its size are common, and so is the management of storage space on which data is saved. Such a task becomes overwhelming when it comes to emails and email clients. Because emails are no longer simple text messages. They contain large files as attachments and other unique data that can make their sizes much larger than usual. Therefore, managing how the data is stored on the servers, files, and on your local computer is often a skilled task.
OST file size limit (Issues & Solutions)
Today we are talking about something similar in the realm of emails and email clients. But this problem is slightly different than what most people struggle with.
In most cases, the data on the server gets big enough for the storage capacity of the mail server. Each email provider offers a limited quota to save emails on their servers. For Gmail, it is 15 GB if you are a free user. General everyday email users do not ever cross this limit, but if you are a heavy corporate user, any limit might seem small to you. Moreover, the custom email providers (like for personal websites) have much smaller storage limit on their servers, and that can be problematic when the space runs low.
The usual practice in such a scenario is to archive emails from servers to local files and keep them as backup after deleting them from the servers, freeing up the space in the process. This makes those emails not available on the servers and so you cannot access them from any other location than your own computer where the backup is saved locally.
But the problem we are discussing today is the opposite. It is about enough storage on your mail server but the technical limit on the file the emails are stored is not big enough for your purpose. This can happen when you are using Outlook with Exchange.
If you are a paid Exchange user, you might get a lot of storage capacity for your emails that it will be long before you run out of space. However, if you are a heavy email user, you might face another issue, and that is: the OST file that stores those emails have a technical size limit too.
Default OST file Size Limit is 50 GB
By default, the OST file size limit is 50 GB. For older versions (before 2010), it is 20 GB. If this limit is crossed, it won’t be able to save more data on the file and you will start receiving synchronization errors. Outlook will fail to download data from the servers to the local file and it might even stop syncing the changes you make altogether.
But the good news is that you can modify the OST size limit and make it larger for your purpose. This will stop the syncing errors of Outlook from server to client and will also solve other issues if you are experiencing any.
However, it must also be noted that Outlook has placed this size limit to OST file for a reason. The larger the file, longer it takes Outlook to respond and to function quickly and properly. Depending on the configuration of your computer, you might experience some performance issues and occasional slowing down of Outlook.
How to modify the size limit for OST file?
You can modify and increase the default size limit for Outlook OST file through the registry of your computer.
- First open the registry editor on your computer. Press the Windows + R Key to open the “Run” command. Then type “regedit” and hit OK. Hit Yes in User account control.
- Inside the registry editor, browse to the following folder of registries:
the number ’16.0’ might be different depending on your Outlook version.
12.0 for Outlook 2007
14.0 for Outlook 2010
15.0 for Outlook 2013
16.0 for Outlook 2016/2019 and Office 365
Also note that there is no registry for OST but only for PST. However, the settings here apply to both format. You can modify the size limit for both OST and PST files.
- If you cannot see the PST folder for registry, you need to create it yourself. Right click on “Outlook” on the left pane and click New à Key, and name it “PST.”
- Inside “HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\PST,” you need to create a new entry, if you cannot already see the entry for “MaxLargeFileSize.”
- Right click on an empty space on the right pane and go to New à D-WORD (32 bit) value.
- Type “MaxLargeFileSize” and press enter. Edit this entry and inside “Value Data,” enter the new limit for the file you want. This is a value in MB, so to set the limit of 100 GB, enter 100000.
- Also do not enter any large number as it might break Outlook functionality. As a general rule of thumb, it is recommended to keep it under 100 GB.
- Then, restart your computer.
You can also add another entry inside “PST” folder named “WarnLargeFileSize.” This will make Outlook warn you before this size is crossed. So, generally, if you want the limit to be 100 GB, you can set the warning size to be around 90 GB.
Congratulations, the OST file size limit and PST file have been increased from their default limit of 20 or 50 GB. Now, if your Exchange server or any other mail provider offers this much space, you will not have any problems working with it and will not face any sync errors.
Keep in mind, though, that a large OST and PST file also requires a better configuration computer for not experiencing any performance lag. Because Outlook has set the limit of 50 GB for modern versions based on the average computer specifications and response time. But if you know your computer can handle the large files or if you are okay with some slowdown in speed, then you can increase the limit without any fuss over it.
We hope this article has been helpful to you in solving any OST sync issues with Outlook due to size crossing the OST file size limit.