Windows Network Protocol Configuration on the Workstation / Client
Computers
By default, newer installations of Windows default to a network protocol SMB2 and SMB3 that is faster than SMB1 but which usually causes damage to shared data files. I.e. it will often damage Shopkeeper data even though it is fine for Microsoft Office documents and web browsing.
All computers need to be configured with SMB1 turned on and SMB2 and SMB3 and OpLocks turned off.
While all computers have to be configured correctly, the most important first step is to configure the Main / Server computer correctly and then proceed to configure the workstations (the other "client" computers.)
The instructions directly from Microsoft are on this support page: http://support.microsoft.com/kb/2696547
(SMB configuration cannot be done via the registry for workstation / client computers.)
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At each Windows 7 or 8 or 10 workstation ("client") computer, turn on SMB1 and turn off SMB2 and SMB3
Press the Windows start button and on Windows 8 this may show the "Tiles" interface, on Windows 7 and 10 it should show the Start menu. Either way, even if it doesn't look like a good place to type, type on the keyboard CMD which should show CMD.EXE or Command Prompt. Right-click on that option and choose Run as Administrator.
In the (often white on black) command screen type these four lines, pressing the <Enter> key after each.
sc.exe config lanmanworkstation depend= bowser/mrxsmb10/mrxsmb20/nsi
sc.exe config mrxsmb10 start= auto
sc.exe config lanmanworkstation depend= bowser/mrxsmb10/nsi
sc.exe config mrxsmb20 start= disabled
A good way to do this is to highlight and right-click and copy the four lines above to the Windows clipboard, then right-click an empty area in the command prompt window and choose Edit, Paste.
Here are the four command lines in graphic form - in case your browser or email split the lines
Here are a dditional recommended Windows settings. In the Registry under this key:
HKEY_LOCAL_MACHINE\system\CurrentControlSet\Services\LanmanWorkstation\Parameters
The following DWORD registry values should be created (if non-existent) with the value set to 0 (zero):
FileInfoCacheLifetime
FileNotFoundCacheLifetime
DirectoryCacheLifetime
Restart the workstations afterwards and verify that they can still talk to the file server - i.e. open My Computer / This PC from Windows and make sure that the mapped network drive letter pointing to the Main / Server computer can still be opened.
FYI, with Windows 8 and above, you can check which version of SMB is enabled, by typing this command at the Powershell prompt
Get-SmbConnection