These changes prevent mapped drives from automatically disconnecting, and also improve file locking behavior. Copy the below into FILESHARING.REG, right-click and merge.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Parameters] "autodisconnect"=dword:FFFFFFFF [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Parameters] "EnableOplocks"=dword:00000000 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Parameters] "IRPStackSize"=dword:00000020 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Parameters] "SharingViolationDelay"=dword:00000000 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Parameters] "SharingViolationRetries"=dword:00000000 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\Parameters] "Size"=dword:00000003 [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MRxSmb\Parameters] "oplocksdisabled"=dword:00000001