User Profile Synchronization Service Stuck at "Starting" - Solution

While configuring User Profile Synchronization in SharePoint 2010, User Profile Synchronization service got stuck at "Starting" state. User profile synchronization service was in starting state for long time! I've been banging my head for couple of Hours.

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After a while, tried running the FIM client from: C:\Program Files\Microsoft Office Servers\14.0\Synchronization Service\UIShell\miisclient.exe , FIM gave an Error Message: Unable to connect to the synchronization Service. found the root cause of the issue! 

Solution was: The account I currently logged-in is a Local Administrator account, but not SharePoint Farm Admin! Logged off and logged in with Farm Admin account. Tried stopping the service which was in "Starting" state.

How to stop the User Profile Synchronization service which got stuck at "Starting" state?

In some cases,  user profile synchronization service may started and then stopped. But here, user profile synchronization service hangs! Lets seek help from our friend: PowerShell!  Get the User profile Synchronization service's GUID and pass it to Stop-SPServiceInstace cmdlet.

Get-SPServiceInstance > Services.txt

This will get all the services along with their GUID to a text file, say "services.txt". Open the file and get the GUID of  User profile Synchronization service which will be in Provisioning state.

Once you get the GUID, execute: Stop-SPServiceInstance and provide the GUID




Restart the Server

worked this time!

In an another case, when we tried re-creating the user profile service application, had the same issue. Fix for this issue was to Remove ForefrontIdentityManager certificates from these 3 locations.
Personal
Trusted Root Certification Authorities
Trusted People
This is because, when I deleted an existing user profile service, it didn't delete the certificates and when recreating it caused the issue!

Enabling or Disabling Classic or Claims Based Authentication

First, make sure your site (web application) does not have the CBA enabled.

Go to Central Administration >> Manage web applications and click on the site you’re planning to enable CBA.
Under Web Applications tab click on the Authentication Providers icon and a small window will pop-up. Under Default you should see Windows.







Next, create a PowerShell (.ps1) file using Notepad and paste the following code into it:

$setcba = Get-SPWebApplication "http://YourSiteURL" $setcba.UseClaimsAuthentication = 1; $setcba.Update() Give it a name, like SetCB.ps1 and save in under C: on your SharePoint 2010 server.

Open SharePoint 2010 Management Shell, make sure you’re under C: (use CD.. to move under C:)and type or Copy and right-click Paste this command ./SetCB.ps1




Hit Enter and after few seconds your SharePoint site should have Claims Based Authentication enabled.
Repeat the previous steps to check if your site has CBA enabled, Central Administration >> Manage web applications and click on the site, click on the Authentication Providers icon and under Default you should see now Claims Based Authentication.




To revert back to Classic mode authentication (disabled Claims Based Authentication) just change the 1 to a 0:

$setcba = Get-SPWebApplication "http://YourSiteURL" $setcba.UseClaimsAuthentication = 0; $setcba.Update()