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disconnected shares

Here is another trivial annoyance of Windows that (over the period of a day) can really slow down your work-flow or train-of-thought. The symptom is that whenever you are trying to open a file via an Open-File dialog, the application just hangs on you for about 5 minutes before returning the focus to you. This happens when you have some network shares previously established. The full condition is that Windows automatically disconnects network shares after some period of time. Invoking the OpenFile dialog from any application forces it to reestablish each of the shares and this can take a very long time.

The short of the solution is to modify a parameter in the registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters\autodisconnect

Just change the value to ffffffff. Here is the official Microsoft details