Editing Amstrad CPC 664 Troubleshooting Guide (section)

== AMSDOS Error Codes ==

AMSDOS reports a small set of error codes when a disc operation fails. These are returned at the BASIC prompt and are listed below.

{| class="wikitable styled-table" style="width:100%; text-align:center;"
|+'''AMSDOS error reports'''
! Message !! Likely cause
|-
| Drive A: disc missing || Drive door not closed, disc absent, or disc-present microswitch dirty
|-
| Drive A: read fail || Drive belt slipped, head dirty, or disc damaged
|-
| Drive A: write fail || Write protected, or drive head failing
|-
| Drive A: disc is read only || Write-protect tab in protect position
|-
| Bad command || AMSDOS RSX (bar command) not recognised &mdash; verify spelling
|-
| Bad file name || File name does not match 8.3 AMSDOS pattern
|-
| File not found || File not in directory; verify with CAT
|-
| Disc full || No free directory entries or no free clusters
|-
| Cannot write to file || File already exists and write-permission is set deny
|-
| Press a key || AMSDOS retry prompt &mdash; press a key to retry the operation, or Esc to abort
|}

For "Drive A: read fail" repeated multiple times on different discs, the drive itself is the suspect &mdash; verify the drive belt and head condition before the disc.