Issue: (Example – A trial install to network license)
Your licensing type has changed and you need to change the licensing option within the program.
Delete LGS.data file in the following folder:
C:\ProgramData\Autodesk\CLM\LGS\ProductKey_ProductVersion.0.0.F
For example, when you originally installed the program, you had a Perpetual license with a serial number, but now you’ve switched to a Subscription license, which does not use serial numbers. When this is the case, you may receive the message that you need to contact your administrator to be granted access to run the program or you may not see the option to sign in to your Autodesk account.
Alternately, the program may have originally been installed as a standalone license, but you need to use a network license server for the product, instead.
Solution:
There are two ways to change the licensing type for your Autodesk products.
If you can access the program, even as a trial:
At the top-right of the screen select the drop-down triangle next to the user name to display a drop-down list.
Click “Manage License…” to open the License Manager screen.
Locate the product and click “Change license type” next to the product.
Close the product once and start it again.
On the Let’s Get Started screen select the appropriate license type and follow the prompts.
LGS Screen
If the above screen does not appear, delete LGS.data file in the following folder:
Windows:
C:\ProgramData\Autodesk\CLM\LGS\ProductKey_ProductVersion.0.0.F
MAC:
\Library\Application Support\Autodesk\CLM\LGS\ProductKey_ProductVersion.0.0.F
If the product is not accessible as Single-User license:
Windows
Note: The below folder/files could be hidden. Make sure to enable view for hidden files/folders in Windows.
Close any running Autodesk programs.
Sign out and Exit from Autodesk Desktop App and A360, if you are using them.
Go to C:\ProgramData\Autodesk\ and delete the ADUT folder
Go to C:\Users\\AppData\Roaming\Autodesk\ and delete the ADUT folder
Delete the 3 files that begins with the adskflex in C:\ProgramData\FLEXnet.
Delete the file LoginState.xml in C:\Users\\AppData\Local\Autodesk\Web Services
Restart the software – you will be asked to repeat the activation process
Mac
Note: The below folder/files could be hidden. To navigate to specific path, in Finder click on Go > Go to folder… paste the path and hit Enter.
Close any running Autodesk programs.
Sign out and exit from A360 if you are using it.
Turn off Time Machine if it is running.
Remove all files under /User//Library/Application Support/Autodesk/ADUT
Navigate to /Library/Preferences/ and locate the FLEXnet Publisher folder.
From within the FLEXnet Publisher folder, delete all files that start with adsk.
Note: Other products might use this licensing technology. Adobe may have some files in this location as well. Do not remove any non-Autodesk files.
Go to /User//Library/Application Support/Autodesk/Web Services and delete the file LoginState.xml
Launch the Autodesk product to re-initiate the activation.
Original Article here.