a simple fix
first of all don’t panic
the disk image is probably not damaged
and will probably not damage your system
this error message was introduced in tiger
think of it as a sort of spell-check for disk images
a proper disk image should have a specific file structure for it’s file type
if the disk image you are trying to mount has a mixed or outdated file structure
you will get this error
i most commonly see this error when i am mounting a dmg file that was created by a ‘dumb’ conversion of a toast image
toast creates certain invisible desktop files which it needs to mount an image
these files are not needed and don’t belong on a dmg image
here’s how to fix it
convert the dmg file to a read-write format
mount the r-w dmg [ignore any errors]
examine the contents of the root level of the mounted image in a list view with “filebuddy” [from skytag software]
delete un-needed invisible desktop files
unmount the image
convert it to read-only uncompressed
[uncompressed images will compress much smaller if you are going to compress the finished image]
[rar often produces much better compression than zip]
mount the new dmg
if you deleted the right files, the dmg should mount without error
as far as copying errors is concerned -
“I tried creating a empty dmg… and drag [ing] my files from the CD…It chokes on an installer file (.pkg) saying “The alias “app name” cannot be copied to the destination, perhaps because the destination does not support this type of alias”.”
this is a permissions error
os x 10.4+ is permissions crazy
you can try checking “igore permissions on this volume” in the the finder’s “get info” window
but the best way is to make a read-write dmg of the mounted disk and follow the proceedure above
as an alternative you can create a cdr image which is read-write by default and then convert it to dmg using the proceedure above