Run a batch file during wix installer startup

[rvorray]

I have a Wix 3.11 based installer that installs files into networked mapped drive D:

I have a component that copies couple of .bat files into C:\windows<custom>
All the rest of the files will be copied into a folder structure in D:\

As mentioned, D: is a network mapped drive and the .bat file that I have maps the network drive D:

I have below setup:

<CustomAction Id="CA_WixSetupInitDDrive_"
                        Directory="Dir_WixSetupInit"
                        ExeCommand="[Dir_WixSetupInit]installer-autofix-for-shared-mapped-drive-on-D.bat /silent /do_not_check_privileges"
                        Execute="deferred"
                        Return="ignore" />

<InstallExecuteSequence>
                <Custom Action="CA_WixSetupInitDDrive_" After="CostFinalize">NOT Installed</Custom>
</InstallExecuteSequence>

This either gives errrors 2732 or 2762 or 2707 meaning that the batch file is not present in the expected location for it to run. Error codes description: https://learn.microsoft.com/en-gb/windows/win32/msi/windows-installer-error-messages?redirectedfrom=MSDN

And if I set the CA to run to run After="InstallInitialize" then I get 'not enough disk space on D:' error as, I believe, Wix is trying to do Cost analysis on D: drive which is not mapped yet!

I cannot avoid using .bat files and using network mapped D: drive. The script itself works fine if it is run by itself. I am unable to figure out the right place in the install-sequence to run it!

What would be the solution here?