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Q&A: MacFixIt Answers

Readers ask about batch-editing file names, augmenting the flash storage in new MacBooks, and secure-erasing e-mail messages in Mail.

MacFixIt Answers is a feature in which I answer Mac-related questions e-mailed in by our readers.

This week, readers asked about how to batch-edit files to add missing file extensions so they can be read in an applicable program, the options for adding more space to a MacBook Pro system with fixed flash memory, and the possibilities for secure-erasing e-mail messages from within Apple's Mail program.

I welcome contributions from readers, so if you have any suggestions or alternative approaches to these problems, please post them in the comments!

Question: Batch-addition of file extensions to unreadable files.
MacFixIt reader Glenn asks:

After installing MS Office for Mac, I have been able to open all of the files except for text files originally created in Word, but which do not have the .doc extension. When double-clicked, these files open in Terminal. If I add the appropriate suffix (.doc) to the file name, the file will open correctly. Is there a way (program or action) that I can use to add the suffix to a large number of file names rather than have to do it individually?

You can use a tool like Better Finder Rename to do this. Alternately, you can do this with Automator, by creating a workflow to get specified files or a specific file type, and then pass these files to the "Rename Finder Items" action. For this action, change it to "Add Text" and set the text to be ".doc" and added "as extension."

Question: Adding more storage to a MacBook Pro with fixed flash memory.
MacFixIt reader Leiv asks:

I purchased a new MacBook Pro some months ago; it has only 128 GB storage. I soon realized that I did a big mistake not upgrading the storage when purchasing. I thought I could upgrade later which is not possible, from what I understand. What is the best and most practical/user-friendly option for additional storage, say up to 1TB? Will any external storage device do, or are any recommended/preferable from a technical point?

(Answer updated below; original is as follows) If the system is a Retina MacBook Pro, then unfortunately you will be limited to what it was shipped with. These systems also do not have optical drive bays so there is no option to add more internal storage by using a bracket in the drive bay. Your only option is to use an external storage device with these systems. Thunderbolt-based devices will be the fastest, but will be the most expensive. However, any drive will do just fine for the most part. I'd recommend you get at least a USB 3.0 drive, as this should be fast enough for most uses. Beyond this, these drives should be, for the most part, indistinguishable for the system.

UPDATE: There is an upgrade available for the Retina MacBook Pro, such as the Aura Pro from Other World Computing, which can be installed following several video guides that OWC and others have online.

Question: Preventing recovery of mail that has been deleted from the hard drive.
MacFixIt reader Art asks:

How can I delete mail so that it cannot be recovered from the drive? In Finder, there is a secure delete, but not in Mail.

Unfortunately this is not supported. Your best bet for securing e-mail in this way is to either keep it all on the server and prevent retention of a local copy, which can be done by selecting your account in the Mail preferences, and then choosing to keep all messages and attachments on the server in the "Advanced" tab. Alternately, you can enable FileVault on your system to ensure the entire hard drive is encrypted. A second option is to use Disk Utility to "Erase Free Space" on your drive after the e-mails have been deleted, but if you have an SSD then this is not recommended. It will also take a while for the drive's free space to be erased in this way.

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