There appears to be a bug with the FeatureCompareSizeRequired in InstallScript. I have a large, multi-disk installer, which installs about 30 GB of data. Many users have small C: drives, and another volume, perhaps E: for data. I've tested this on a VM, and it appears that no matter what, the FeatureCompareSizeRequired function only checks the size of the C: drive.

For example, with the following code, C drive has 22 GB of free space, and E drive has 45 GB of free space, and user tries to install to E:\data, the "Not Enough Space" message still occurs!!! I put in a message box, to tell me exactly what path it was comparing, and it returns the correct path

...
nResult = SdSetupType2(szTitle, szMsg, szDir, 0);
if (nResult = BACK) then
goto Dlg_SdWelcome; // user clicks Back to go back to Welcome dialog
else
nSetupType = nResult;
if (nSetupType != CUSTOM) then
nSize = 0;
MessageBox("Comparing size of " + szDir, INFORMATION); // -----> This returns "Comparing size of E:\data" !!!!
FeatureCompareSizeRequired( MEDIA, szDir, nSize );
if (nSize != 0) then
MessageBox( szSdStr_NotEnoughSpace, WARNING );
goto Dlg_SetupType2; // reloads the current dialog
endif;
endif;
....

Also, the function name "FeatureCompareSizeRequired" is apparently too long of a string to search for, and too long of a tag to use in this forum. What? O.o