"Error getting file security.." How do I resolve this?

Should you see an error message similar to the below during a re-install or upgrade to DSM version 4.0,

simply rename the 'SpaceClaim' folder in 'C:\ProgramData\' to something else and restart the DSM v4 install.

This occurs in cases where the folder was present from a previous DSM install but the new installer does not have sufficient permissions to overwrite & create a new folder with the same name.

Note that this folder does not contain any files linked to your paid add-on modules.