Runtime Error 71: “Disk not ready,” explained and fixed

Error 71, “Disk not ready”, is a legacy error from the removable-media era: the drive is present, but there is no readable medium in it, an empty floppy or card reader, a CD drive with no disc, or media still spinning up. On modern systems it survives mainly around card readers, optical drives, USB devices that enumerate before they are usable, and network drives in a half-connected state. The device exists; it just cannot answer yet.

For people who just run the program

  1. Check something is actually in the drive. An empty card reader slot is the modern classic: Windows assigns it a letter, the program addresses the letter, and error 71 reports there is nothing to read.
  2. Wait a few seconds and retry after inserting media or connecting. Drives need a moment to become ready after media is inserted or a device wakes; code that polls immediately can beat the hardware.
  3. Reconnect the network drive. A half-connected mapped drive can report not ready rather than unavailable; clicking it in Explorer forces the reconnection.
  4. Report the drive letter. “Error 71 on the card reader” is a complete diagnosis; the letter identifies which device the program expected to be loaded.

For people who write the code

  1. Check IsReady before working. The FileSystemObject Drive object exposes IsReady precisely for this state. Testing it turns a cryptic 71 into a prompt like “insert the card in drive G:”:
    2. If fso.GetDrive("G:").IsReady Then
    ' proceed with the read
Else
    MsgBox "Drive G: has no media inserted."
End If
  2. Retry briefly for waking devices. External drives that sleep need spin-up time. One or two retries spaced by a second distinguish “not ready yet” from “not ready at all” better than an immediate failure.
  3. Do not enumerate every drive letter blindly. Code that probes A: through Z: will meet empty readers and unready devices as a matter of routine. Enumerate drives that exist (the Drives collection) and test readiness per drive.
Error 71 is not corruption. Nothing is wrong with the media or the data; the drive simply had nothing readable at the moment of the call. Treating it as damage leads people to reformat perfectly good cards and discs.

If it still happens

If a fixed internal drive reports not ready, treat it as hardware: check the disk in the manufacturer's diagnostics and confirm the drive appears correctly in Disk Management. A fixed disk that intermittently is not ready is failing in a way no code change addresses.

Common questions

What is the difference between error 71 and error 68? Error 68 means the device cannot be reached at all, such as an unmapped drive letter. Error 71 means the device is there but has no ready medium, such as an empty card reader.

Why do empty card readers cause this error? Because Windows gives the reader a drive letter even with no card inserted. Programs addressing that letter meet a drive that exists but cannot be read, which is exactly error 71.

Related errors

Runtime Error 68 · Runtime Error 57 · Runtime Error 61