Error: The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine.

使用 LinqToExcel 突然發生 error，原來是安裝 windows update 後，發生的慘案
Error: The 'Microsoft.ACE.OLEDB.12.0' provider is not registered on the local machine.

解決方案如下：

1. uninstall KB4041676 on Windows 10 and KB4041681 on Windows 7.

2. Find prior version (4.0.9801.0) of msexcl40.dll

3. Place in another directory. They suggest the application directory, but since in the next step you will modify registry to point to this older version, it can probably go anywhere.

4. Update registry key HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Jet\4.0\Engines\Excel\win32 to point to the location from step 2.

但此招是救急，可能有安全性的疑慮！