[FONT="]Like a number of people, I used the Samsung data migration tool to transfer my Win7 operating system from one SSD to a larger one, and afterwords discovered that Windows would not start unless both drives were plugged in. I have spent the better part of 6 days trying every "Try this and see if it works!" solution I can find on the net, and none of them have worked for me. The original drive is an 840 EVO, the new one a 512 GB Samsung 951 NVME.[/FONT]
[FONT="]A boot with only the 951 connected fails with a winload.exe missing error, and then booting from the install CD into Windows "Repair my Computer" results in the notice that Windows can't automatically fix the issue, and manual Startup Repair produces a no hard drive found message. From the command prompt, only the "Data" partition is recognized on the drive by Diskpart, which makes me think that the partition table on drive C may [FONT="]an issue[/FONT].[/FONT]
[FONT="]When booting with both drives attached, the Starting Windows screen appears for about 90 seconds before the log on screen comes up. The system behaves normally from that point on, with the exception that the restore function is inoperative –from both a backup file or a rescue disk. Obviously, the startup process spans both the original and the new drive, but I cannot sort things out so that the operating system [FONT="]starts [/FONT]from the new 950 drive independently. After a week of frustration, I really, really hope [FONT="]someone[/FONT] here can[FONT="] diagnose[/FONT] what's [/FONT][FONT="][FONT="][/FONT][/FONT][FONT="] going [FONT="]wrong [/FONT]in the startup process and 2 explain how [FONT="]to[/FONT] fix it.[/FONT]
[FONT="]The first image below is the disk management panel, and the second is the File Explorer view of the 840 (original) drive files.[/FONT][FONT="] The third image is the Explorer view of the C partition on the C: drive, and the last is a shot of the contents of the "Data" partition on that drive.

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[FONT="]A boot with only the 951 connected fails with a winload.exe missing error, and then booting from the install CD into Windows "Repair my Computer" results in the notice that Windows can't automatically fix the issue, and manual Startup Repair produces a no hard drive found message. From the command prompt, only the "Data" partition is recognized on the drive by Diskpart, which makes me think that the partition table on drive C may [FONT="]an issue[/FONT].[/FONT]
[FONT="]When booting with both drives attached, the Starting Windows screen appears for about 90 seconds before the log on screen comes up. The system behaves normally from that point on, with the exception that the restore function is inoperative –from both a backup file or a rescue disk. Obviously, the startup process spans both the original and the new drive, but I cannot sort things out so that the operating system [FONT="]starts [/FONT]from the new 950 drive independently. After a week of frustration, I really, really hope [FONT="]someone[/FONT] here can[FONT="] diagnose[/FONT] what's [/FONT][FONT="][FONT="][/FONT][/FONT][FONT="] going [FONT="]wrong [/FONT]in the startup process and 2 explain how [FONT="]to[/FONT] fix it.[/FONT]
[FONT="]The first image below is the disk management panel, and the second is the File Explorer view of the 840 (original) drive files.[/FONT][FONT="] The third image is the Explorer view of the C partition on the C: drive, and the last is a shot of the contents of the "Data" partition on that drive.

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My Computer
- Computer type
- PC/Desktop
- Computer Manufacturer/Model Number
- Scratch built
- OS
- Win7 Pro 64 bit
- CPU
- i7 5930K
- Motherboard
- Asus X99-E WS/USB 3.1
- Memory
- 32 GB Crucial Ballistic DDR4
- Graphics Card(s)
- EVGA GTX 980 ti
- Sound Card
- Xonar Essense STX
- Hard Drives
- Samsung 950 Pro 512 GB, Samsung 840 EVO 250 GB, WD 1001FALS 1TB
- PSU
- Corsair RM1000
- Case
- Fractal Define R5
- Cooling
- Corsair Hydro H100i
- Internet Speed
- 75 Mbps down / 6 up
- Antivirus
- MS
- Browser
- Firefox