Well friends I followed the path of doing a full fresh install of Windows 10 on my "new" z620 and only install what is really bare nescessity. I had to install a specific Windows driver for my Transcend SD - USB 3.0/3.1 reader that prompted a reboot.
Event ID: 158 is logged for identical disk GUIDs.
fixed with this link
https://support.microsoft.com/nl-nl/kb/2983588 and I needed to install and configure MPIO in the Windows Features itself.
After applying the feature I did not experience any issues like I had before.
Fingers crossed.
Things I did not do are
1. install the Driver Chipsets from HP for my z620
2.install the Intel Rapid Storage Technology Enterprise Driver
3. install or upgrade the Intel Management Engine Firmware Update and Utilities
Sofar no issues I am very hesitant to install the Intel Driver Chipset Drivers for Windows 10.
Your thoughts MtothaJ, Brian1965, BambiBoomZ ?
PS just my thoughts on the Boot Block, would it be a financial worthwhile enterprise to start a business in updating the boot block date and how to go about it ?
In The Netherlands where I live and work there are alot of z workstations now being offered and not too many being sold at what we would call a reasonable price level reflecting the boot block date.