Hidden Share - Can't properly share out access as I could on Windows 7

I'm in an enterprise, domain environment. I have a Windows 10 Enterprise desktop that is acting as a backup system for my small IT group (we do have servers for this but want to use this system for certain data).

I replaced Windows 7 Pro with Windows 10 Ent (clean install). Have a secondary HDD, created a local group and added my team's domain user accounts to that local group. That group has full control over the secondary drive under the security tab.

I used to be able to permission the driverletter$ in this manor on Windows 7 and when my team would from a regular end users's computer and account, browse out to \\desktop\g$ it would prompt for their credentials and get right to the root of the drive. Now, it does prompt but denies them with this in the event log:

An account was logged off.

Subject:
Security ID: ADMIN\TeamUsername
Account Name: TeamUsername
Account Domain: ADMIN
Logon ID: 0xB3E7D0


Logon Type: 3


This event is generated when a logon session is destroyed. It may be positively correlated with a logon event using the Logon ID value. Logon IDs are only unique between reboots on the same computer.

Can't edit: Basically, I need my team to be able to get to this hidden share while logged on as another user that doesn't have access, I want them to be prompted for their credentials and be let right in.... Windows 10 must have changed something as I could do this in Windows 7.