SQL Server FCI installation with Mount Point permissions issues

You may need to set permissions on the mount point volume instead of at a folder level. I suspect this is the issue you're running into.

From Guidelines for Setting SQL Permissions on Mount Point Folders (highlighting is Microsoft's):

Gotchas

Unfortunately, it is still possible to set/view permissions on the mount-point root folder via Windows Explorer, which can lead to unexpected results because the permissions of the mount-point root folder may seem valid and you can see “proper” inherited permissions, however these are not the permissions applied to the mounted volume.

• https://connect.microsoft.com/SQLServer/feedback/details/569895/installation-of-sql-server-2008-r2-on-mount-points-fails

Guidelines

1. It is recommended that you do not place any files directly in the mount-point root folder. This will make permissions management much simpler, because the tendency is to always check the folder permissions, which in this case is misleading. Instead, create a subfolder under the mount-point root folder, and set the proper permissions to that subfolder. Since the subfolder is a regular folder, the folder permissions you observe and set are indeed the permissions being applied. So using the previous example, you would want to create a new folder: D:\FolderForVol3**SubfolderXYZ**. Now, set your folder permissions against that new SubfolderXYZ folder as you normally would.
2. If you absolutely must place items directly in the mount-point root folder (Not the recommend approach), then you will need to set volume permissions, not folder permissions. Recall, that this is because the mount-point root folder permissions are not the permissions which will actually get set on the mounted volume (because the mount-point root folder is not a real folder). You can set volume permissions as follows:
   • Start->run->diskmgmt.msc (View the properties of a volume http://technet.microsoft.com/en-us/library/cc740097.aspx )
   • Select the volume->Properties->Security tab
3. If you are adding a new folder for SQL to use, be aware of the required permissions for SQL access:
   • Beginning with SQL Server 2012 permissions are assigned to the per-service SID for each of its services. http://msdn.microsoft.com/en-us/library/jj219062.aspx
   • Configure Windows Service Accounts and Permissions http://msdn.microsoft.com/en-us/library/ms143504.aspx

The way I had to solve this was by using the cacls.exe utility. Detailed instructions for it can be found here. I suspect your command to grant full permission to a user would be as follows:

cacls E:\MSSQL\Log\L1 /M /E /G YourUserName:F
cacls E:\MSSQL\Data\Tempdb1 /M /E /G YourUserName:F

You'll want to run this for your account and the SQL Server Service Accounts or group(s) as well.

Final note here, it is imperative that you include the /E flag, otherwise it will overwrite permissions on that path. This behavior carries additional side effects of ulcers and heavy drinking, so make sure you don't forget the edit flag when running this command.

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Another option is to delete the drives and repartition them from scratch. They're still likely messed up from the original attempt at setting up security via Windows Explorer (e.g. check out the Gotcha clause from the first MS article).

In this case if you still want to write to the root folder on the mount path, you'll want to use the cacls utility. I would also suggest setting up three sub folders on E:\ such as Data, Logs, and TempDB and then install everything to the sub folders. Don't nest the mount points into a directory you'll install files to.