When launching or running Lightroom on Windows, you get the Server Busy error dialog:
The action cannot be complete because the program is busy. Choose 'Switch To' to activate the busy program and correct the problem.
Try the following solutions, in order. After performing each solution, relaunch Lightroom to check if the issue is resolved.
Solution 1: Install the latest Lightroom update
Adobe has made changes to the way Lightroom initializes and talks to the connected services, which should fix most cases. In Lightroom, choose Help > Updates.
See the following links for more details:
Solution 2: Disable the Superfetch service in Windows
Solution 3: Install graphics card (GPU) driver updates
The updated drivers are available from the card manufacturer’s website (such as nVidia, ATI/AMD, or Intel).
Simply running the Windows update doesn’t ensure that you have the most recent video driver. Go directly to your card manufacturer's website to check for driver updates.
To determine what video card you have and to download/install the most current driver, see Microsoft's articles Update drivers in Windows 10.
Your video drivers are included with your operating system updates. Make sure that you have installed all the latest OS updates by choosing Apple menu > About This Mac > Software Update.
Solution 4: Temporarily disable any 3rd party utilities such as anti-virus that may be causing a conflict