15. XP (SP1, 2 or 3) appears to lose permission to access File Shares on Vista or Server 2008 x86 or x64

XP display "%Share% is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. Access Denied" when previously it has worked fine. It may happen a couple times a day or less frequently. Often a reboot of the Vista or Server 2008 machine appears to temporarily fix it.

PLEASE BACKUP THE REGISTRY BEFORE TAKE ANY CHANGES. Click on File | Export.

You can do the following (for more of an on/off toggle):

1. Run "regedit".

2. Expand and locate the sub tree as follows.

HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters

3. Add a new REG_DWORD key with the name of "Smb2" (without quotation mark)

Value name: Smb2

Value type: REG_DWORD

0 = disabled 1 = enabled

4. Set the value to 0 to disable SMB 2.0, or set it to 1 to re-enable SMB 2.0.

5. Reboot.