Mac Users: Migratable Recovery
vs. Salvaging for Files
Information About Your Macintosh® Recovered Data
Note: The following applies to the Apple OS X® Operating System.
Your recovered data set is:
- Migratable
- By File Type
IMPORTANT! PLEASE INSPECT YOUR DATA IMMEDIATELY. THEN BACK IT UP.
FOR YOUR PROTECTION, WE ROUTINELY ERASE ALL MEDIA USED TO RECOVER OR CONVEY YOUR DATA USING SECURE TECHNIQUES. DATA SAVERS, LLC, CANNOT BE RESPONSIBLE FOR SUBSEQUENT DATA LOSS. BACKING UP YOUR IMPORTANT DATA TO MULTIPLE DEVICES IS YOUR BEST DEFENSE.
Overview: Your Recovered Data
"Recovered" data is just that— data that has been salvaged or mined from a defective hard drive or other storage medium. The process is a little bit like raising a sunken ship: often we can recover the vessel intact, but sometimes all that remains are bits and pieces.
The overall success of the recovery (and the quality of the recovered data) depends upon the extent of the damage. For example, it is impossible to recover data from drive surfaces where a head crash has gouged the media, turning the data into dust.
Many drives fail with bad sectors (defects on the surface of the media), and in most cases, we can recover data from them. However, we cannot recover data if it is truly "gone", i.e. missing, corrupted, or overwritten.
Depending upon the extent of the damage, the recovered data you receive back from us will likely be either migratable data or data by file type. The important distinction is this:
Migratable data allows a computer to be restored much like it was before the crash, retaining your applications, preferences, desktop items, and users; whereas data by file type may or may not retain the original order of the files, and some may be numbered (instead of named).
Obviously, migratable data is preferred over data by file type. What determines the difference? The key is the integrity of the drive's directory structure.
The Directory
A drive has a directory, which is a catalogue or index of the files on the drive. It includes the file names and the dates of file creation or modification.
An analogy— somewhat dated— is that the directory is like the card file in a library that keeps track of where the books are located on the shelves, the names of the authors, etc.
If the directory of a damaged drive is intact or in reasonably good shape, then the files that are recovered will generally be well organized, in the manner that they were before the damage occurred. This is the case for migratable data.
However, if the directory is missing or severely damaged, then we must use other techniques to recover the data and to arrange it.
Using our analogy, a badly damaged directory is like dumping the card catalogue on a busy street. We might be able to reconstruct part of it, but the only way to be sure what is in the library is to actually go to the shelves and take inventory. This is the case for recovery by file type.
Migratable Data
One of the benefits of Apple's OS X operating system is that it allows the user to move or migrate data from one Mac to another (the folks from Redmond can't do that with their OS).
This is a great feature for upgrading computers, but we also can take advantage of it for post-recovery data restoration. If the recovered data is migratable, then we can return it back onto the original computer.
Data can be migrated to an Apple Macintosh® computer running OS X versions 10.3.x (Panther™) or 10.4.x (Tiger™) in two ways:
Fresh or New System Installation
When the operating system is first installed, it prompts the user whether or not to transfer data from another Mac. At that point, the recovered data is on a hard drive that is placed in a Firewire enclosure and connected to the computer. The computer will regard the Firewire drive as another computer and complete the transfer of the original data. After reboot, the users, desktop, etc. are restored. Note: the data must be in good shape or the transfer may fail or report errors.
Migrating User Data to an Existing Installation
Tiger (OS X 10.4) includes a utility called the Migration Assistant that can import information (e.g. users, applications, files, etc) from another computer or hard drive partition. The program is located in the Utilities directory: Hard Drive (e.g. Macintosh HD) / Applications / Utilities.
Note that the Migration Assistant has rules and limits: you cannot copy or combine information from the same user to your machine. However, you can rename the user (to be transferred) in order to migrate the data.
If you change the transferred user name, the user information, libraries, applications, etc. must be manually copied over with respect to the rules governing file permissions. The "how to" of that process is beyond the scope of this guide.
Data by File Type— Scavenging for Files
When the hard drive's directory or catalogue is damaged or missing, then we scan all of the readable surfaces of the drive for files. Typically, we create three folders of recovered data, as follows:
Macintosh HD (or whatever you named your hard drive, if different). The data inside of this folder will— hopefully— be organized just like your original drive, including Applications, Library, Users, & System folders. Some files may be missing or are corrupt, or have broken links, but much should be useful.
We don't recommend using the Migration Assistant to transfer this data to a new installation, because it is possible that the transferred data will have problems launching applications and the like. It is safer to copy items over manually to their proper locations once you have verified them.
CBR Files are scavenged from the drive and placed into generic folders by category and then file type. A Microsoft Word file might be placed inside of an Office folder nested inside of Documents. This is a very comprehensive process, and the recovered data may include damaged, partial, or previously deleted files.
These files are recovered independent of the drive's directory or catalogue— which records the name of the original file, the creation date, size, location, etc.— so none of this information is available. The files that are recovered in this manner are numbered instead of named, and the creation date is always the recovery date.
The chief drawback of the file type recovery method is that each generic file must be opened and identified, renamed and saved. The only way to know what you've got is to wade through the folders.
If a file is corrupt it may not open. Repairing these files is typically very difficult, requiring advanced techniques and a lot of time.
Often there are hundreds of JPEG photo images. If you have Adobe Photoshop, you can use the Browse function to sort through the images without having to manually open each one.
Orphans This is a catch-all category that often includes obscure system support files and other odds-and-ends. It usually does not contain much that is of interest or use to the end user. Nonetheless, it is worth browsing through the folders to see if there is something of value.
Additional Information on Recovery by File Type
You may notice that the volume of the recovered data exceeds your drive's original size! This is because there is overlap between the CBR and other folders, because anything that the software interprets to be a valid file will be scavenged.
If the directory of the drive was severely damaged, and the software cannot recreate it, there is a possibility that some specialized file types may be missing. There is a technical reason for this:
The scan process searches for snippets of code called grep expressions that identify the type of file to follow. One particular grep expression identifies a Microsoft Word® file; another a text file; yet another a JPEG image, etc. All of these software tools have a finite list of file types that they can identify, and they do not recover some of the less common file types. For example, if person uses ProTools® , the software may recover the "standard" musical components (e.g. WAV, MP3, AIFF) but not the entire ProTools compositions.
In "mission critical" situations, we can work with the various software manufacturers to see if they can identify and add the grep expression in question. However, the outcome of this effort is uncertain, and it adds additional time and cost to the recovery process.
The process of restoring individual files to their "proper" places is relatively easy when it concerns user files and other documents. However, libraries, fonts, and other support files are trickier and this process is not a part of our standard data recovery procedure.
Factors that Effect Overall Yield
The physical condition of the source drive will determine the yield or the quantity of data that is recovered. For instance, a drive may have a damaged head, and we will use special techniques to recover data "around" the damaged area of the associated platter. If a drive has four data platters and one of them is unreadable, the theoretical maximum we can recover is 75%.
In that case, the amount of useful data will recover will be somewhat less than the theoretical maximum. The reason is that part of a file may be on the damaged platter. This problem is made worse if the drive is badly fragmented. However, we do not recommend that you defragment a drive unless you have it totally backed up, as such efforts have been known to scramble a drive and create a need for data recovery!
The only other option for recovering from drives that have damaged heads is to replace the head stack, which requires expensive clean room repair.
Rarely, bad drives may degrade or fail completely during the process of extracting data from then, even though we use fast state of the art equipment for this purpose. If this happens, we will notify the client immediately to apprise them of any other options.
IMPORTANT GENERAL INFORMATION
If we Reinstalled your Operating System
If we reinstalled the operating system for you, please note that we use DVD or CD media, which is not the most current version.
The first thing you should do (immediately before or after you back up your recovered data!) is to check for Software Updates under the Apple on the top menu bar, and download the most current version.
Please note that certain programs (such as iTunes®) may not work correctly until you do. Others (e.g. Microsoft Office®, Adobe Photoshop®, etc.) may report that they are being opened for the first time, or you may be required to re-authenticate. This is normal.
iTunes
As noted above, do not use iTunes until you have updated your operating system to the most current version. When you first launch the program, you will have to relink or import your existing music library into the new program. The iTunes library is located in the Music folder that resides in your User or Home folder.
What if there are Problems with the Operating System or Applications?
When appropriate, we will restore a damaged operating system. We do this as an accommodation and do not charge for it separately unless we upgrade the system version (e.g. from Panther® to Tiger®), in which case you will have to purchase a new Apple software package.
If we perform a migration recovery, your applications, User folder, personal settings, etc. are added "on top of" the operating system. If there are problems with your library or user settings, the problems will also migrate along with the software.
Should this occur, try reinstalling the operating system (doing an archived reinstallation to preserve your programs and settings) or remove and reinstall the offending application.
Please note that troubleshooting problems with the operating system or applications are separate from the data recovery process, and that we do not warrant the operation of the recovered data, including the operating system and applications.
We will try to help if needed, but additional labor charges may apply.
What Should I Do with My Old Drive?
Keep it in a safe place. In the case of a disaster such as the loss of your equipment, this may be the sole repository of your data. However, should you elect to dispose of it, we will destroy the data on it at no additional charge.
Thank You for Using Data Savers, LLC.
Call us at (770) 939-9363 or email service@datasaversllc.com if we can answer questions or be of service.