Can't import SharePoint online Powershell module

Manual removing CSOM assemblies from the GAC is not a good idea - especially if you have SP on-prem running on the same server. Problem is caused by several instances of SPO SDKs and may be solved this way:

1. Open Control Panel -> UnInstall Programs -> Search for SharePoint related setups.
2. Locate SharePoint Client Components -> Uninstall.
3. Locate SharePoint Online Management Shell -> Uninstall.
4. Ensure that anyone of the above setup is installed more than one time. If so, remove all the instances.
5. Now, open the Powershell console in administrative mode (Run as administrator).
6. Uninstall SPO Powershell module (If already exists) by running this command: Uninstall-Module -Name Microsoft.Online.SharePoint.PowerShell -AllVersions -Force
7. Finally, install the latest SPO Powershell module by running this command: Install-Module Microsoft.Online.SharePoint.PowerShell -Force