My question revolves around increasing the maximum mailbox size in outlook and what the dword values represent in the registry.

I recenetly encounted a problem where someone I support reached a 20gig mailbox size in outlook 2007 which is the maximum default size in outlook. The exchange server has an unlimited size limit; however the local machine imposes a 20gig limit. I was easily enough able to go into the registry, create the PST key in HKCU\Software\Microsoft\Office\12.0\Outlook and created the 4 dwords, MaxFilesSize which I set to 30 gig (I think), MaxLargeFileSize I left the same, WarnFileSize set to 29 gig (I think), and WarnLargeFileSize I left the same.

What I can't figure out is what the values mean. According to a Microsoft, http://support.microsoft.com/kb/832925, , The defaut size is 7bb04400.
****before going to that link, just an FYI, part of it is wrong. What microsoft has listed as MaxLargeFileSize and MaxFileSize, the values should be reversed. MaxFileSize is defauted at 20gig, not 2gig.****

So 7bb04400 = 2075149312 is the decimal representation of 20gig in the registry.

What I'm having problems understanding is the decimal representation of 20gig. Is that 207,519,312 bytes or 207,519,312 kilobytes or something completly different?

If I put that number into a byte to gigabyte converter, it comes out as 2 gig. If I do a kilobyte to byte conversion, it comes out as 2000 gig, or 2 terabytes. I have no idea how the dword registry calculates how large to make the outlook mailbox.

What unit of measurement is 2075149312?

Edited by kes166

5 Years
Discussion Span
Last Post by kes166

I've figured this out for whoever cares to read this. I made a mistake, MaxFileSize refers to an ANSI format. 7bb04400 - 2075149312 is measured in bytes and is 2gb. It's for a standard before outlook 2003.

The MaxLargeFileSize is the DWord that uses UNICODE and is default of 00005000 which is hex for 20gig.
If we change that to 00007800 it will equal 30720 which is measured in megabytes which will equal 30gig.

So basically,

Quoted Text Here

In the following table, the MaxLargeFileSize registry entry and the WarnLargeFileSize registry entry refer to a UNICODE formatted (new Large format) file, and the MaxFileSize registry entry and the WarnFileSize registry entry refer to an ANSI formatted (an earlier Microsoft Outlook format) file. The UNICODE values are set in megabyte (MB) increments, while the ANSI values are set in byte increments

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