Windows 10: Outlook.Com.OST Size Difference When Uploaded to OneDrive

My local Outlook.Com.OST file is 537.640kb. When I upload it to OneDrive it shows 525MB.Why the size difference?Thank you!

:)

 

Copy Outlook .ost file to an offline device

If you are the owner of the Exchange profile, you can configure your account in the Outlook in the new computer and simply download the mailbox data from the Exchange server. But if you want to transfer OST file data
to another user, you can convert OST to PST and then transfer it to the new computer. The new user can import the PST file to his mailbox.

Let’s start the process:

Step 1- Locate OST in your system

To locate an OST file in your system, follow the below-mentioned steps:

·
Open Control Panel and click on Mail.

·
Select Email Accounts in the “Mail Setup” dialogue box.

·
Now, go to the Data Files tab and select the desired account.

·
Click on Open File Location to know the location of the OST file.

·
The location of your PST file will be opened

Step 2- Convert OST to PST

In this step, you need to convert OST to PST. Though you can export OST mailbox data to PST using
the Export feature of Outlook and you can use any third party OST to PST Converter.

 

Changing the File Type on an Outlook *.OST file.

I did a stupid thing and inadvertently changed the file type of an Outlook 2016 OST file to a PDF file. I have tried to change the type of file that *.OST is used by to Outlook but Windows 10 does not let me. Does anyone have any suggestions.

Thanks

 

Outlook 2013 tells me to delete the .ost to continue with new emails

Dave, This suggests a different method of finding it - Introduction to Outlook Data Files (.pst and .ost) - MSSupport There's also this Locating Outlook data and configuration files - MSSupport Denis