[wix-users] Why is modifying a PrimaryVolumePath with CustomAction revert back if I set TrackDiskSpace="yes"

[Shintaro Takechi]

Hi,

Using custom action, I am attempting to modify PrimaryVolumePath while
Dialog has a flag TrackDiskSpace="yes".
It is successful as you can see from the log below. (It was performed in
CA_Debug)
However, when I do overwrite the property, the next moment, it is reverted
back to original.
Why is this?

MSI (c) (F8:04) [17:41:37:262
]: PROPERTY CHANGE: Modifying PRODUCTDESTINATION property. Its current value is
'G:\sampleInst\'. Its new value: 'C:\sampleInst\'.
MSI (c) (F8:04) [17:41:37:263]: Doing action: WixUIValidatePath
Action 17:41:37: WixUIValidatePath.
Action start 17:41:37: WixUIValidatePath.
MSI (c) (F8:90) [17:41:37:266
]: Invoking remote custom action. DLL:
C:\Users\X\AppData\Local\Temp\MSI8EEF.tmp, Entrypoint: ValidatePath
Action ended 17:41:37: WixUIValidatePath. Return value 1.
MSI (c) (F8:04) [17:41:37:279]: Doing action: CA_Debug
Action 17:41:37: CA_Debug.
Action start 17:41:37: CA_Debug.
MSI (c) (F8:EC) [17:41:37:283
]: Invoking remote custom action. DLL:
C:\Users\X\AppData\Local\Temp\MSI8F00.tmp, Entrypoint: DebugCA
MSI (c) (F8!A0) [17:41:37:431
]: PROPERTY CHANGE: Modifying PrimaryVolumeSpaceAvailable property.
Its current value is
'5872688872'. Its new value: '379637872'.
MSI (c) (F8!A0) [17:41:37:432
]: PROPERTY CHANGE: Modifying PrimaryVolumePath property. Its current value is
'G:'. Its new value: 'C:'.
Action ended 17:41:37: CA_Debug. Return value 1.
MSI (c) (F8:04) [17:41:37:452]: Doing action: WixUIValidatePath
Action 17:41:37: WixUIValidatePath.
Action start 17:41:37: WixUIValidatePath.
MSI (c) (F8:44) [17:41:37:455
]: Invoking remote custom action. DLL:
C:\Users\X\AppData\Local\Temp\MSI8FAD.tmp, Entrypoint: ValidatePath
Action ended 17:41:37: WixUIValidatePath. Return value 1.
MSI (c) (F8:04) [17:41:37:778
]: PROPERTY CHANGE: Modifying PrimaryVolumeSpaceAvailable property.
Its current value is
'379637872'. Its new value: '5872688872'.
MSI (c) (F8:04) [17:41:37:778
]: PROPERTY CHANGE: Modifying PrimaryVolumePath property. Its current value is
'C:'. Its new value: 'G:'.

Any input would be appreciated.

Thank you