It is because there is no unallocated space right next to the system reserved partition. When you select the target partition and try to expand it, you will only find the Extend Volume feature is grayed out. Solution: You cannot resize or extend system reserved partition with Windows built-in tool Disk Management. Since upgrading to newer Windows needs more space on the System Reserved partition, Windows will not upgrade until it detects that the System Reserved partition has enough space.
On Windows 7, the system reserved partition takes up 100MB disk space, 350MB on Windows 8, and 500MB on Windows 10. You won't have the error on previous versions before Windows 7 since the system reserved partition first appears on Window 7. Why: This Windows upgrade error is usually caused by insufficient space on the system reserved partition which stores important boot files and normally locates before C: drive (the system partition). Please tell me how to extend system reserved partition on a GPT drive? Finally, I know the reason is that the system reserved partition has no enough space. Windows update says: We couldn't update the system reserved partition.
Symptom: Recently I want to update my Windows 7 to Windows 10, but there is something wrong with the installation.
