Dell states that on their newest models (including OptiPlex 7040's and Latitude E7270's), Windows 7 is only supported on non-NVMe hard drives.
See also
Cornell's research on this issue
From: Joshua A. Gerner
Sent: Friday, November 11, 2016 12:52 PM
To: MANAGED-WIN-L
Subject: Dell computers, NVME storage and Windows 7
Hi, all.
Desktop Engineering, in concert with unit TSP's, have recently spent considerable time troubleshooting issues with imaging Windows 7 on the latest Dell desktop and laptop models. These problems do not occur with imaging Windows 10.
The issues appear to be confined to computers that are coming with NVMe (Class 40) rather than SATA (Class 20) SSD hard drives installed.
It turns out that Dell actually has a document up now that states that on their newest models (including OptiPlex 7040's and Latitude E7270's), Windows 7 is only supported on non-NVMe hard drives.
http://www.dell.com/support/Article/us/en/4/SLN301149
Because of this Dell support statement, and our recent troubleshooting experience...
1. Desktop Engineering strongly recommends that if you are purchasing new models for Windows 7 deployments, you select the non-NVMe hard drive option.
2. Desktop Engineering will no longer be testing or supporting Windows 7 imaging on computers with NVMe hard drives.
We have confirmed that the M.2 form factor NVMe and SATA drives can be swapped interchangeably. We are working to have language inserted at both the CIT standard bundle page as well as within e-Shop describing the OS and hardware compatibility.
Let us know if you have any questions or concerns (<MD-PC>), or as always feel free to contact me directly.
Thanks,
Josh Gerner
Desktop Engineering
Cornell Information Technologies, Infrastructure
607-255-7096