diff --git a/packages/fpmkunit/src/fpmkunit.pp b/packages/fpmkunit/src/fpmkunit.pp
index 8b80c2456a..5eb5aae6e3 100644
--- a/packages/fpmkunit/src/fpmkunit.pp
+++ b/packages/fpmkunit/src/fpmkunit.pp
@@ -6666,7 +6666,7 @@ begin
     GlobalDictionary.AddVariable('unitinstalldir',Defaults.UnitInstallDir);
     GlobalDictionary.AddVariable('packageunitinstalldir',APackage.GetPackageUnitInstallDir(Defaults.CPU,Defaults.OS));
 
-    D:=IncludeTrailingPathDelimiter(Defaults.BaseInstallDir);
+    D:=FixPath(Defaults.Prefix);
     // This is to install the TPackage.Installfiles, which are not related to any
     // target
     if InstallPackageFiles(APackage,[],D) then