Every time I run the Media Creation Tool from Microsoft (to create a Windows installation media/ISO), it sits on the following message for quite a long time before it actually starts:
Getting a few things ready
What exactly is it doing at this stage, prior to actually downloading the ISO? It makes me nervous, and it says nothing more than that vague, cryptic "headline".
During the "getting things ready" phase, SetupHost.exe (which was extracted into C:\$Windows.~WS\Sources by the main Media Creation Tool program) is obtaining the list of downloadable Windows distributions for the various editions, architectures, and languages.
It quickly downloads products.cab (<50 KB) from Microsoft, quickly unpacks it into a multi-megabyte products.xml file listing all those distributions, and then spends the vast majority of the phase very inefficiently parsing that file. If you disassemble/debug it with the official debugging symbols, you will find the time spent in the CMoOnlineStore::LoadOffers function in SetupCore.dll, which uses various members of the confusingly named "Unattend" family of functions to extract the various attributes from each record in the XML file.
You can confirm this more easily by watching Task Manager during this phase and seeing that the process is using CPU virtually exclusively. You can also observe the process during this phase with Process Monitor and see it doing virtually nothing (just what look like status reports to me). In summary, nothing nefarious is happening, just wasted CPU cycles.
