SD Card Clone on Windows (OS Transfer)¶
Last updated: 2026-04-10
Cloning an SD card to another SD card on Windows using HDD Raw Copy Tool.
The main gotcha: Windows auto-mounts new partitions mid-clone and steals the device lock → error (5) = ACCESS_DENIED.
The Problem¶
Clone starts, partition table lands on the target disk, Windows sees new partitions and auto-mounts them — stealing the write lock back. Next block write → ACCESS_DENIED. Typically dies early (~64 MB in).
Fix: Disable Windows Automount Before Cloning¶
Run in admin PowerShell:
Inside diskpart:
automount disable— stops Windows from grabbing newly-appearing partitionsautomount scrub— clears cached mount points from previous failed attempts
Then remove any leftover drive letter (e.g. F:) that got assigned during the failed attempt:
Get-Partition -DriveLetter F -ErrorAction SilentlyContinue | Remove-PartitionAccessPath -AccessPath "F:\"
No error if F: is already gone — that's fine.
Retry the Clone¶
Open HDD Raw Copy Tool again — same source, same target, hit START. Windows won't interrupt mid-clone this time. Expect ~60–80 min at 14 MB/s (USB SD reader bottleneck).
Speed tip
14 MB/s is USB SD reader limited. A UHS-I built-in slot or USB 3.0 reader on the source side roughly doubles speed. Not required — just leave it running, but don't let the laptop sleep.
If it gets past ~500 MB without dying, you're almost certainly home free — the auto-mount race only triggers early, right after the partition table lands.
After Clone: Restore Automount¶
Don't leave automount disabled permanently — future USB drives won't get drive letters.
Inside diskpart:
Summary¶
| Step | Command |
|---|---|
| Disable automount | diskpart → automount disable + automount scrub |
| Remove stale drive letter | Remove-PartitionAccessPath -AccessPath "F:\" |
| Run clone | HDD Raw Copy Tool — full run |
| Re-enable automount | diskpart → automount enable |
Tools¶
- HDD Raw Copy Tool — sector-level clone, works for any media
- diskpart — Windows built-in disk management CLI