I get the following error when I try to launch Turbotax for the first time after installing it. "turbotax is already running under another account. Error 70001"

When you were installing the software it must have left something running.  Try restarting your computer.  You may also have to restart your internet service.

@prashanthsharma 

Turbotax cust support was finally able to resolve the problem. After trying a bunch of other things, forcing a "manual update" of TurboTax fixed it. 

You will need to download the update from Intuit website directly and run it.