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On Windows 8, I have mapped a network drive to Z:, which resides on a Mac computer on my homegroup on my gigabit network. When I mount a disk image (roughly 10 GB) on the network drive, such as an ISO file for an application, and then install it, the image unmounts after about a minute.

How can I stop it from unmounting? The Mapped Network Drive itself does not disconnect; only the disk image is unmounted.

I think that specifically in my case, the problem has to do with the fact that I am mounting a large disk image over a network. Because if I simply copy the 10 GB file to my local computer, then it finishes. So, how do I mount a large disk image over a network, and install a program from it?

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up vote 1 down vote accepted

I would recommend to increase the CIFS timeout.

Here follows some examples from the MSDN blog

Client session timeout It is the most common exchange timeout. This is defined in [MS-CIFS] as a system-wide parameter Client.SessionTimeoutValue. This value can be configured through the SessTimeout registry key [KB102067]. \HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters\ Value type: Dword Value name: SessTimeout Default: 45 seconds (Windows NT) Default: 60 seconds (Windows 2000)

Extended session timeout This optional timeout may be useful in high latency networks. It applies to a timed exchange with a server listed in ServersWithExtendedSessTimeout. \HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters\ Value type: Dword Value name: ExtendedSessTimeout Default: 1000 (seconds) Value type: Multi-string Value name: ServersWithExtendedSessTimeout Default: These were introduced in Windows XP.

Offline file timeout The client uses this optional timeout for a timed operation on an offline file, normally indicated by the FILE_ATTRIBUTE_OFFLINE attribute. This timeout can be configured with the registry parameter \HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters\ Value type: Dword Value name: OffLineFileTimeoutIntervalInSeconds Default: 1000 This was introduced in Windows 2000.

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This looks like your first post here. And it's an incredibly useful one! In particular, the "Client session timeout" section is relevant. I had to create the "SessTimeout" key because it didn't exist for me (I think it was defaulting to 45 seconds). I created it as a REG_DWORD, with a Decimal value of 600 (for 10 minutes), and that did the trick! It takes effect immediately, so no restart or even re-connection to the share necessary. Do you know if there are any downsides to increasing this value to such a high number? I guess it just keeps the connection open longer? – Gary Jul 15 '13 at 16:54
Thanks for your nice comment. I hope I can continue contributing to this great forum. – Gonzalo Murillo Jul 23 '13 at 6:57

I believe that on windows, it has been my observation that when a network attached drive is idle after some period of time, then it is disconnected from the network. However, when use resumes, it will reattach. All perfectly normal.

Thus I am not sure of your issue, is it that the drive never reconnects.

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In my particular case, I'm trying to mount a large disk image (10 GB) over a network, and install a program from it. However, the image is unmounted after about a minute, and I'm not sure why. Copying the disk image to the local computer and installing it via that method works fine, of course, but I'd like to avoid the step of copying it if possible. – Gary Jul 15 '13 at 4:51

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