When installing an Autodesk product (such as F/X CAD or AutoCAD), you received an error message similar to the following:
.NET 4.5 is not installed. AutoCAD 2016 cannot be installed without this component. See your system administrator for more information.
A problem with the Windows .NET Framework is preventing your Autodesk product from installing correctly.
You can correct this issue by temporarily changing the Windows .NET Framework currently installed on your computer.
Step 1: Change Your Version of .NET to 4.5
1. Press the WINDOWS and R keys (Windows keyboard) or Command and R keys (Mac keyboard) to open the Run window.
2. Type REGEDIT, and click OK.
3. Navigate to and select the following Registry Key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Client
4. In the right pane, note the value of the Version key in the Data column. (In our example, the Version value is 4.5.50938.)
Then double-click the Version file.
Make a note of the current version at this point (in our example, the version is 4.5.50938). You'll need to restore this version at the end of these steps.
5. In the Edit String dialog box, change the Value data to 4.5.
Step 2: Install AutoCAD or F/X CAD
Close the Registry Editor, and install your version of F/X CAD or AutoCAD.
7. Once finished, go back into Regedit, and repeat steps 4 and 5 above, changing the .NET version back to its original value. In our example, we'll change it back to version 4.5.50938.
For further information, please see the official Autodesk solution to this issue.
Can't change the reg key because you're not the administrator?
You might be receiving an Access denied or Error while deleting key message when trying to change reg keys. Both of these messages are the result of not having administrator status.
To resolve this issue:
1. Select a key you want to edit.
2. Right-click that same key.
3. Select Permissions from the menu that opens.
4. Select the System option from the Group or user names. Check the Allow box next to Full Control. Then click Apply.
5. Set Full Control to Allow in the same way for the System option.
You should now be able to edit reg keys.