I have purchased 11 of these units and all 11 are working perfectly.  However, you need to understand these are reconditioned units.  The solid state drives and hard disk drives that come with the system are older units that have been in service.  On two units I had to go into ROM setup and reset everything to the default settings.For my office I downloaded the Windows 10 Pro install files to a thumb drive from Microsoft.  Then I replaced the drives that came with the units with a Samsung EVO 860 solid state drive.  Being Dell units the Windows 10 Pro product code is stored in the system ROM.  I just booted from the thumb drive and the installation went perfect.  Also, the drives that come with the units will also boot up and install just fine if you want to use them.  I did not pay the extra for solid state drives on the later units I purchased.  Since I was installing new drives I just took the hard drives out, installed the EVO 860 drives and installed Windows Pro from the thumb drive.So far I am about 6 months out and all systems are working like new ones.