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Reg key for Maximum number of shellbags, Windows 7

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HexDrugsRockNRoll
(@hexdrugsrocknroll)
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Joined: 17 years ago
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Topic starter  

Has anybody had any success identifying the default maximum number of shellbags within Windows 7?

I've seen the Microsoft support articles which detail adding the BagMRU size key and value yourself within Windows 7, but have yet to personally see a case where the key is already there (even though in testing I can see via Procmon Windows searching for it (unsuccessfully) when I access folders and move them around).

Appreciate anyone shedding light or providing guidance on this.


   
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zoltandfw
(@zoltandfw)
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Joined: 13 years ago
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As far as I know, the default value was 400, but since Vista it is 5000 now. Since the "BagMRU Size" is a DWORD (32-bit) Value, the maximum would be an unsigned integer 2^32 - 1, so 0 - 4294967295. Note I have not tested if the maximum is actually implemented.


   
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jaclaz
(@jaclaz)
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Joined: 18 years ago
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As far as I know, the default value was 400, but since Vista it is 5000 now. Since the "BagMRU Size" is a DWORD (32-bit) Value, the maximum would be an unsigned integer 2^32 - 1, so 0 - 4294967295. Note I have not tested if the maximum is actually implemented.

The 5000 should be referring to Windows XP.

See
http//www.dfrws.org/2009/proceedings/p69-zhu.pdf

jaclaz


   
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HexDrugsRockNRoll
(@hexdrugsrocknroll)
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Joined: 17 years ago
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Topic starter  

Thanks zoltandfw and jaclaz.

So if the key is there, the number can be up to ~4.2 billion (possibly). But what if the key isn't there, as I'm seeing now? Does it just continue to grow until something falls over?

Old XP machine images I've looked over do indeed have it set to 5,000 as default, but, like I said, there's nothing on the Windows 7 images I have.


   
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jaclaz
(@jaclaz)
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Joined: 18 years ago
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Old XP machine images I've looked over do indeed have it set to 5,000 as default, but, like I said, there's nothing on the Windows 7 images I have.

It seems like the "default" setting was increased from 400 (original XP and SP1/1a) to 5000 in SP2 and that however the maximum on XP is 8000.

I believe (but I may well be wrong) that the default value (i.e. when the key is missing altogether) is still 5000, see also here
http//superuser.com/questions/260391/cant-find-the-bagmru-size-value-my-folder-settings-are-getting-lost
where it is hinted that apart the theoretical 32 bit number limit, the max is anyway 20000 or so.

jaclaz


   
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HexDrugsRockNRoll
(@hexdrugsrocknroll)
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Topic starter  

Cheers jaclaz! Appreciate the link.


   
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