World Magazine 2024
Troubleshooting Boot Process Errors
The BIOS performs a power-on self-test (POST) when it starts up the system, to check out the PC and make sure that everything is working properly. Assuming that the BIOS is able to boot the system far enough to gain access to the video subsystem, it will display information about the PC as it boots. It will also use the video system to communicate error messages to the user. In fact, most boot problems are displayed via video error messages, as opposed to audio beep codes. For more information on beep codes, see AMI Beep Codes or Award Beep Codes.
An error message can be produced by various different parts of the system during the POST process, depending on how far into the boot process the system gets before it is occurs. Most error messages are produced by the system BIOS, as it is responsible for most of the functions occur during boot. Other error messages are operating-system-specific.
There are many thousands of individual error messages; some are more common than others because there are only a few different BIOS companies that are used by the majority of PCs out there today. You should note though that the exact wording of an error message can be changed by the manufacturer of each system or motherboard, thereby providing for a multitude of variations.
In most cases, the messages are pretty similar to each other, and you may see slightly different wording in the error message you see as opposed to the ones listed here. Essentially though, if the messages appear similar, it is probably safe to follow the diagnosis here. “Disk drive failure” and “Diskette drive failure” are what we would consider similar in nature, however you may want to consult your motherboards owner’s manual regarding any unusual messages, or to ensure that your manufacturer means the same thing with their messages that other companies do.
Additional Notes:
- We have tried to list all the error messages in alphabetical order for simplicity, however you may find a few that appear out of order. These were intentionally inserted out of order to place them with error messages that are similar or fit a certain category.
- Some BIOS POST messages you will see in all UPPER CASE and some will be found in a mix of UPPER and lower case. We have used the mixed upper and lower case for easier reading.
| A20 Line or 8042 Gate Error | Keyboard Clock Line Failure |
| Detected Short in Address Line | Keyboard Controller Failure |
| BIOS ROM Checksum Errors | Keyboard Data Line Failure |
| Level 2 Cache Failure | Keyboard Error |
| CH-1 Timer (Timing) Error | Keyboard Error or No Keyboard Present |
| CH-2 Timer (Timing) Error | Keyboard Error: nn |
| CMOS Battery Fail | Keyboard Interface Error |
| CMOS Battery Low | Keyboard is Locked – Unlock |
| CMOS Checksum Error – defaults loaded |
Keyboard is Locked – Unlock the Key |
| CMOS Checksum Error | Keyboard Locked |
| CMOS Checksum Failed | Keyboard Stuck Key Failure |
| CMOS Display Type Mismatch | Memory Access Failure |
| CMOS Memory Size Mismatch | Memory Address Error at xxx |
| CMOS Information Invalid | Memory Failure at xxx, read xxx, expecting xxx |
| CMOS System Options not Set | Memory Parity Error at xxxx |
| Clearing a Corrupt CMOS | Memory Size has changed since last boot |
| CMOS Date and Time Not Set | Memory Size in CMOS Invalid |
| CPU Reported as XXX (Where XXX = speed) |
Memory Test Fail |
| Disk Boot Failure – Insert system disk and press Enter |
Memory Test |
| Disk Boot Failure | Memory Verify Error at xxx |
| Diskette Boot Failure | Missing Operating System |
| Diskette Drive Failure | No Boot Device |
| Diskette Drive x Failure (with x= 1, 2, A or B) |
No Boot Device Available – Press F1 to retry boot |
| Diskette Drive or Type Mismatch Error – Run Setup |
No Boot Sector on Hard Disk |
| Diskette Read Failure – Press F1 to restart system |
No Boot Device Available – Press F1 to retry boot, F2 for setup utility |
| Display Adapter Failed – Using Alternate |
No Boot Sector on Fixed Disk – Press F1 to retry boot |
| Display Switch is Set Incorrectly | No Boot Sector on Fixed Disk – Press F1 to retry boot, F2 for setup utility |
| Display Type has changed since last boot |
No ROM BASIC – System Halted |
| Display switch not proper | No Timer Tick Interrupt |
| DMA #1 Error | Non-system Disk – Replace and press any key |
| DMA #2 Error | Not a Boot Diskette |
| DMA Bus Timeout | Not a Boot Diskette – Press F1 to retry boot |
| DMA Error | Operating System Not Found |
| Error Encountered Initializing Hard Drive |
Option ROM Checksum Failure |
| Error Encountered Initializing Hard Drive Controller |
Override Enabled – Defaults Loaded |
| Error with Hard Disk | Parity Check |
| Failing Bits: xxx Memory Access Problem |
Parity Error ???? |
| Fixed Disk Controller Failure | Press F1 to Disable NMI, F2 to Reboot |
| Fixed Disk Read Failure – Press F1 to Retry Boot |
Primary Master Hard Disk Failure |
| Fixed Disk Configuration Error | Primary Slave Hard Disk Failure |
| Fixed Disk Failure | Real Time Clock Error |
| Fixed Disk x Failure (where x may be 0, 1, 2 or 3 or A, B, C or D etc) |
Real Time Clock Failure |
| Floppy Drive Mismatch | RAM Parity Error |
| Floppy Disk Controller Failure | ROM Error |
| Floppy Disk Controller Error or No Controller Present |
Secondary Master Hard Disk Failure |
| Floppy Disk(s) Fail | Secondary Slave Hard Disk Failure |
| Gate A20 Error | Shadow RAM Failed |
| Hard Disk CMOS Mismatch | Shutdown Failure |
| Hard Disk Initializing: Please wait a moment |
Static Resource Conflict |
| Hard Disk Install Failure | System Battery is Dead |
| Hard Disk Diagnosis Fail | System Cache Error – Cache Disabled |
| Hard Drive Controller Failure | System CMOS Checksum Bad |
| HDD Controller Failure | System RAM Failed at Offset xxxx |
| I/O Card Parity Error at xxxxx | System Timer Error |
| Incorrect Drive A Type | Time of Day Clock Stopped |
| Incorrect Drive B Type | Time of Day Not Set – Run Setup Program |
| Internal Cache Test Failed – Cache is Disabled |
Timer ½ Failure |
| Interrupt Error | Timer Error |
| Interrupt Controller Failure | Unable to Control A20 Line |
| Int #1/#2 Error | Unexpected Interrupt in Protected Mode |
| Invalid Configuration Information – Please Run Setup |
Updating ESCD |
| Invalid Media Type | XXXX ROM Error |
| Invalid Partition Table | XXXXH Option ROM Checksum Failure |
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