Hello this is unusual, so perhaps I'll go through what I do to see if it helps.  Firstly don't use a mapped drive for SharedData - that hasn't been supported properly for a long time.  Use UNC paths i.e. Programs = \\<sageserver>\sage\sage300apps  SharedData = \\<sageserver>\sage\sage300share.  Next, make sure your System path contains the entry \\<sageserver>\sage\sage300apps\runtime;

Ensure the new SQL account you create for the Vault and Store databases has least the public, dbcreator and securityadmin roles allocated.  
  

Make sure you log out and check you can log back into the SQL server with the new account using SQL Auth to test it:

Then ensure you've mapped your new SQL user db_owner permissions to your new databases:
 

Now if you're using a named instance (I always go default if I can), your syntax for this can be painful so try SQLSERVER\Instance or SQLSERVER_Instance.

One thing that is easy to miss is if your SQL server is not the same as your Sage application server, and the firewall is blocking port 1433 or TCP/IP isn't configured on the SQL server, so in this case make sure you download the free SQL Management Studio onto your Sage server and ensure you can log into the SQL server through the management studio from the Sage server.  If you can't login you should get a useful error message.

Also don't forget to check the Event Viewer after you receive the "Failed to establish..." error again.  There should be an entry in the Event Viewer at the same time as the error explaining in detail what is actually causing the problem.

Good luck, let us know how you go!  Tim

Hi Tim,

Thank you so much for your reply. 

I completely redid the everything, and it worked. But I still used Mapped drive though.

Thanks again.

Hi digitmasters that's great news and thank you for letting me know you successfully used a Mapped drive - looks like that's now a valid approach again after they stopped working under Vista and Windows 7.  Its been that long since I last used Mapped drives so I might give them a go again at the next opportunity.  Cheers.

Just note that mapped drives are not available to background tasks. So if you have any custom automation/code then mapped drives will not be available.
You can also have issues where users are assigned a different mapped drive letter than another user - due to GP settings.
I always use UNC paths for those reasons.

Interesting yep I tried again recently - I still can't get a reliable experience using mapped drives, so as much as I'd like to use them its back to UNC for me.