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OST File Size

%3CLINGO-SUB%20id%3D%22lingo-sub-220483%22%20slang%3D%22en-US%22%3EOST%20File%20Size%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-220483%22%20slang%3D%22en-US%22%3E%3CP%3EHi%20experts%3C%2FP%3E%3CP%3E%26nbsp%3Bi%20have%205%20users%20and%20from%20the%20server%20side%20can%20i%20find%20out%20their%20OST%20file%20size.%3C%2FP%3E%3C%2FLINGO-BODY%3E%3CLINGO-LABS%20id%3D%22lingo-labs-220483%22%20slang%3D%22en-US%22%3E%3CLINGO-LABEL%3EAdmin%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EExchange%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EOffice%20365%3C%2FLINGO-LABEL%3E%3CLINGO-LABEL%3EOn-Premises%3C%2FLINGO-LABEL%3E%3C%2FLINGO-LABS%3E%3CLINGO-SUB%20id%3D%22lingo-sub-220498%22%20slang%3D%22en-US%22%3ERE%3A%20OST%20File%20Size%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-220498%22%20slang%3D%22en-US%22%3EOST%20sizes%20depend%20on%20what's%20synchronized%20down%20by%20Outlook.%20The%20slider%20controls%20how%20much%20Outlook%20takes%20down%20into%20the%20OST%20and%20obviously%20there's%20a%20big%20difference%20between%20a%20month%20and%20a%20year%2C%20so%20it's%20impossible%20to%20find%20out%20what%20an%20OST%20size%20is%20with%20any%20precision%20short%20of%20connecting%20to%20the%20PC%20and%20looking.%3C%2FLINGO-BODY%3E%3CLINGO-SUB%20id%3D%22lingo-sub-220488%22%20slang%3D%22en-US%22%3ERe%3A%20OST%20File%20Size%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-220488%22%20slang%3D%22en-US%22%3E%3CP%3EI%20don't%20know%20that%20you%20can%20find%20the%20exact%20OST%20size%20from%20the%20server%20side%2C%20but%20you%20may%20be%20able%20to%20estimate%20it.%26nbsp%3B%20According%20to%3CA%20href%3D%22https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fexchange%2Foutlook%2Fcached-exchange-mode%22%20target%3D%22_self%22%20rel%3D%22noopener%20noreferrer%20noopener%20noreferrer%22%3EMicrosoft%20documentation%3C%2FA%3E%3A%3C%2FP%3E%3CP%3E%3CEM%3E%22When%20you%20use%20Cached%20Exchange%20Mode%2C%20be%20aware%20that%20users'%20local%20.ost%20files%20are%2050%20percent%20to%2080%20percent%20larger%20than%20the%20mailbox%20size%20reported%20in%20Exchange%20Server.%20The%20format%20that%20Outlook%20uses%20to%20store%20data%20locally%20for%20Cached%20Exchange%20Mode%20is%20less%20space-efficient%20than%20the%20server%20data%20file%20format.%22%3C%2FEM%3E%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3CP%3E%26nbsp%3B%3C%2FP%3E%3C%2FLINGO-BODY%3E
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Frequent Contributor

Hi experts

 i have 5 users and from the server side can i find out their OST file size.

2 Replies
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Best Response confirmed by Rising Flight (Frequent Contributor)
Solution

I don't know that you can find the exact OST size from the server side, but you may be able to estimate it.  According to Microsoft documentation:

"When you use Cached Exchange Mode, be aware that users' local .ost files are 50 percent to 80 percent larger than the mailbox size reported in Exchange Server. The format that Outlook uses to store data locally for Cached Exchange Mode is less space-efficient than the server data file format."

 

 

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OST sizes depend on what's synchronized down by Outlook. The slider controls how much Outlook takes down into the OST and obviously there's a big difference between a month and a year, so it's impossible to find out what an OST size is with any precision short of connecting to the PC and looking.