Like many people here, I was also getting the message, "The alias "<shared folder>" could not be opened, because the original item cannot be found." And like many people here, messing with the digital signature setting did not resolve the problem.
Fortunately, I stumbled around long enough to find an answer.
The problem is not with the Mac's configuration, it's in Windows. (Why am I not surprised?) The following (Windows XP) registry value needs to be increased:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters --> LPRStackSize
It's easy to check if your problem accessing Windows can be fixed by making this change. On your Windows machine, go to Control Panel --> Administrative Tools --> Event Viewer and look at the System Log. You're looking for an error message with a source of "Srv" which occurred when you tried to access the Windows machine from your Mac. The description will read:
Then it gives a link you can click to get Microsoft's instructions on how to increase this value.
Here are brief instructions to how to apply this fix in Windows XP:
1. Launch the Registry Editor. (Select Start --> Run... and type in "regedit".)
2. Navigate through the list of folders to find this one:
Code:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\lanmanserver\parameters
3. Look for an entry named "IRPStackSize" in the right pane. If it doesn't exist you will have to create it. To create the entry, right-click in the right hand pane and select New --> DWORD Value. Then enter "IRPStackSize". (I had to create this entry on my machine.)
4. Double-Click the "IRPStackSize" entry to change the value.
5. Click the "Decimal" radio button in the Base group.
6. If there's already an entry, increase the value by a small amount. If it's set to zero, then Microsoft recommends starting at 15. (On my machine, a setting of 18 resolved the problem.)
7. Save your changes by clicking the OK button.
8. Close the Registry Editor and reboot the computer.
9. Test your access from the Mac. If you're still getting the error message, repeat the process to increase the setting a little more.
Of course, the usual caveats about how dangerous registry editing is still apply. You can completely hose Windows if you delete or change the wrong things in the registry, so be very, very careful that you do not make a mistake.
I hope this helps someone avoid all the hair pulling I just went through.
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Ed "What the" Heckman