Disk image invalid at random or unable to mount from Finder
I think I've found a serious problem with 10.4.10 (although it could be an older bug) in verifying and mounting downloaded disk images. In this case the disk images were downloaded from Adobe.
The problem happens at random so I think it is a memory leak bug and possibly caused by disk images that are over 2GB.
For the record, through repeated tests, I've eliminated the network and the source of the downloaded images. I've verified the problem does not occur on an iBook running 10.4.9. The dmg files on both machines are identical both in size and MD5 hash. I've also verified and repaired both the startup disk and permissions.
When mounting the disk image, or verifying the image using Disk Utility the resulting error is either a 'codec overrun' or a 'CRC32 checksum error'. (You might get a similar error if the downloaded file was corrupted enroute.)
Using hdiutil to verify the disk image repeatedly I get the following:
Attempt #1 (OK):
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): verified CRC32 $629FA77D
...............................................................................
verified CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is VALID
Attempt #2 (OK):
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): verified CRC32 $629FA77D
...............................................................................
verified CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is VALID
Attempt #2 (Invalid, exits almost immediately after checking HFS partition.)
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
.
disk image (Apple_HFS : 2): checksum failed with error 1000.
...............................................................................
calculated CRC32 $1D42E2A6, expected CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is INVALID
hdiutil: verify failed - codec overrun
Attempt #4 (Invalid, but runs through most of the file):
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): calculated CRC32 $8C6BE160, expected CRC32 $629FA77D
...............................................................................
calculated CRC32 $ABB152E2, expected CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is INVALID
hdiutil: verify failed - invalid checksum
Attempt #5: (OK)
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): verified CRC32 $629FA77D
...............................................................................
verified CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is VALID
As you can see it's a crap shoot whether or not I can mount this file. The file is valid and mounts repeatedly on the 10.4.9 machine.
In terms of a work around, I can create a DVD of the contents on the working machine and try installing from the DVD. I don't really want to roll back the affected machine to 10.4.9 to test, but this might also be an option to fix the problem.
I checked with Apple Care, but they could not offer anything other than archive and re-install which I don't really feel like doing at the moment.
Note: This may not actually be a problem related to 2GB files. I have a couple of other dmg files around 300MB which randomly pass/fail but maybe a 2GB file starts the problem.
Although hdiutil will occasionally verify the file as valid it seems mounting the image from Finder will always fail. This definitely smells like a memory leak.
Skipping verification and mounting the image won't work as the image will unmount when you read from the disk image at the affected spot.
Macbook White 2GHz Mac OS X (10.4.7)
The problem happens at random so I think it is a memory leak bug and possibly caused by disk images that are over 2GB.
For the record, through repeated tests, I've eliminated the network and the source of the downloaded images. I've verified the problem does not occur on an iBook running 10.4.9. The dmg files on both machines are identical both in size and MD5 hash. I've also verified and repaired both the startup disk and permissions.
When mounting the disk image, or verifying the image using Disk Utility the resulting error is either a 'codec overrun' or a 'CRC32 checksum error'. (You might get a similar error if the downloaded file was corrupted enroute.)
Using hdiutil to verify the disk image repeatedly I get the following:
Attempt #1 (OK):
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): verified CRC32 $629FA77D
...............................................................................
verified CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is VALID
Attempt #2 (OK):
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): verified CRC32 $629FA77D
...............................................................................
verified CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is VALID
Attempt #2 (Invalid, exits almost immediately after checking HFS partition.)
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
.
disk image (Apple_HFS : 2): checksum failed with error 1000.
...............................................................................
calculated CRC32 $1D42E2A6, expected CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is INVALID
hdiutil: verify failed - codec overrun
Attempt #4 (Invalid, but runs through most of the file):
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): calculated CRC32 $8C6BE160, expected CRC32 $629FA77D
...............................................................................
calculated CRC32 $ABB152E2, expected CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is INVALID
hdiutil: verify failed - invalid checksum
Attempt #5: (OK)
Checksumming Driver Descriptor Map (DDM : 0)...
Driver Descriptor Map (DDM : 0): verified CRC32 $2BEFD39B
Checksumming Apple (Apple partitionmap : 1)...
Apple (Apple partitionmap : 1): verified CRC32 $2A6C5D81
Checksumming disk image (Apple_HFS : 2)...
...............................................................................
disk image (Apple_HFS : 2): verified CRC32 $629FA77D
...............................................................................
verified CRC32 $EAF93BBF
hdiutil: verify: checksum of "ADBESTPPCS3_WWE.dmg" is VALID
As you can see it's a crap shoot whether or not I can mount this file. The file is valid and mounts repeatedly on the 10.4.9 machine.
In terms of a work around, I can create a DVD of the contents on the working machine and try installing from the DVD. I don't really want to roll back the affected machine to 10.4.9 to test, but this might also be an option to fix the problem.
I checked with Apple Care, but they could not offer anything other than archive and re-install which I don't really feel like doing at the moment.
Note: This may not actually be a problem related to 2GB files. I have a couple of other dmg files around 300MB which randomly pass/fail but maybe a 2GB file starts the problem.
Although hdiutil will occasionally verify the file as valid it seems mounting the image from Finder will always fail. This definitely smells like a memory leak.
Skipping verification and mounting the image won't work as the image will unmount when you read from the disk image at the affected spot.
Macbook White 2GHz Mac OS X (10.4.7)
