I recently formatted [the hard drive] because I thought it might be the problem- I guess thats not going to do anything if its going to go?
If the hard-drive is in a state of (impending) mechanical failure, then formatting won't make any difference. It's like the foundation of a house crumbling.
I can't say that this
is the case with the problem you describe. It's just as likely to be something weird & unexpected, so try to rule as many different things as possible, one at a time. But the hard-drive is about the most common single point of failure in a computer.
Am I right in understanding that this happens with multiple different CF cards? It would be cheap & easy to try a different card reader. If you're getting random errors in other programs, then look at the system's RAM.
Is md5sum something I need to get, or built into OSX?
Open Applications > Utilities > Terminal. Type 'md5 ' (with the space and without the quotes), drag & drop the image file from the hard-drive into the Terminal window and then hit "enter". Then do the same thing with the original copy of the image on the CF card.
You should see something like this:
Code:
$ md5 /Volumes/WesternD/image.jpeg
MD5 (/Volumes/WesternD/image.jpeg) = ce4f7e38573560b405dcc2813ed897e3
$
The long number is an MD5 "checksum" of the file - it will always be the same for a given file (irrespective of filename, computer, continent or time of day (or timestamp, for that matter)), and two different files will always have different MD5 checksums.
So if you copy the file from the CF card to the external hard-drive, run md5 on them both and the numbers don't match up then you know the corruption is in that transfer (or in reading from the hard-drive subsequently). If you copy from the CF card to your Desktop and the numbers don't match up, then the problem is between the CF card, card-reader and maybe the hard-drive in your computer itself.
This probably sounds kinda complicated, but it may help you to track down where the corruption has occurred if you can still locate the different copies of the file when you get the import error. One thing you can also usefully do is create a textfile containing all the checksums for all the files in a folder. I don't know how often you're seeing this problem, but if you were to keep records of checksums for all copies of your new images for a week or two then you might be able to identify where & when they changed.
Code:
$ md5 Desktop/eBay/* > checksums.txt
$ cat checksums.txt
MD5 (Desktop/eBay/9500S-8ML box.jpg) = 2465636e2b5375669f9d4ed08cf311dc
MD5 (Desktop/eBay/9500S-8ML box.tiff) = 73e731d819012d2e469378447902bc15
MD5 (Desktop/eBay/9500S-8ML main.jpg) = 144e33514c4f360717a8df133dc5716a
MD5 (Desktop/eBay/9500S-8ML main.tiff) = 7989e04ba688505866416ad03752e8b0
MD5 (Desktop/eBay/9500S-8ML serial 2.tiff) = 198b0beaaae44612b1dc457b375c74ec
MD5 (Desktop/eBay/9500S-8ML serial.jpg) = c73630748fdc2c58bfe405ae66637c62
MD5 (Desktop/eBay/9500S-8ML serial.tiff) = 198b0beaaae44612b1dc457b375c74ec
$ open checksums.txt
$
In the example above it's the ">" that says "send the output of the md5 command to a file" - the "*" says "run the command on every file in this folder". `cat` is a command to read the contents of a file onto the Terminal screen and `open` will open a file in the default program associated with the filetype.
Note that "9500S-8ML serial 2.tiff" above gives exactly the same "magic number" as "9500S-8ML serial.tiff", because it's an exact copy of the original file. If I were to open it and crop it and then run the command again then the numbers would no longer match up. The md5sum will change if just a single pixel of the file is changed.
I fear I've made this far more complicated than you'd like. It's the way I would go about tracking down the problem and you did ask!
If you want to know more about this stuff you should probably Google "introduction to Unix on Mac" or something. I consider this pretty essential computer knowledge, but I appreciate that I am a geek, so not best socialised to advise.
Stroller.
