Upgrade from Windows 10 (Creators Update etc) to Fall Creators Update is blocked because the update program reports SEP is not compatible with Windows 10. Even after uninstallation of the SEP client, the update program still reports that SEP is present and not compatible.
"uninstall this app now because it isn't compatible with Windows 10"
Windows Update looks everywhere on every drive (including mapped shared drives) for indications of SEP or its installation files, even if it was never installed or already removed.
How to research which SEP files are blocking the update.
1. Gather all XML files from C:\$WINDOWS.~BT\Sources\Panther folder.
Note: If you cannot find C:\$WINDOWS.~BT folder, check [View] - [Hidden items] on the explorer tab.
2. Check the latest ..._APPRAISER_SetupOutput.xml file, for example, 9IXwybje40aW+P6q.220.127.116.11_APPRAISER_SetupOutput.xml.
You can see some SEP files like in the following example.
This is located under the Property list "Decision Maker" XML-section.
Look some strings up, there should be XML-value of the "Asset" XML-property.
In the "Property-List Type Inventory" section you can find the program path ("lower case long path" XML-attribute). Find all the lines containing: <Property Name="DT_ANY_FMC_BlockingApplication" Value="TRUE"
Look some lines up, there should be XML-value of the "Asset" XML-property.
Under the "Property-List Type Inventory" section you can find the program path ("lower case long path" XML-attribute). This file is preventing the update to finish.