washingtonpost.com
Help File: Spam With Your Return Address; Mac and Windows Disk Formats

By Rob Pegoraro
Sunday, May 24, 2009

QI got a "Postmaster Delivery Status Notification" saying I sent an e-mail to a strange address. How could this happen?

AThe odds are that this reader's computer didn't get hacked -- for one thing, it's a Mac, and there's very little Mac malware afoot.

It's more likely that another computer, on which the reader's e-mail address was saved, got hit with a virus. That virus, in turn, used the reader's e-mail as a fake return address on spam sent from this computer. When some of those junk messages bounced, the notification went to the return address.

But you shouldn't assume that you're fine if you get one of these bounce messages. If you have anti-virus software, use it to scan your system for trouble. Also, check your sent mailbox and make sure that you don't have anything in there that you didn't write yourself. If you also access your account through a Web-mail interface, make sure there's no spam in the Web sent mailbox; the Web system could have been compromised if you logged into it on an already-hacked machine.

I may need to move files between a Mac and a PC. What are the disk formats I should consider?

The simplest option is the one used on most removable disks in Windows, FAT32 (those letters stand for "File Allocation Table"). Macs and PCs can read and write disks in this format. Almost all internal Windows disks, however, use a higher-capacity version called NTFS ("NT File System"); Macs can read that but need help from extra software, such as the free MacFUSE, to write to it.

Macs, in turn, employ a disk format known as HFS ("Hierarchical File System") Plus. Windows can neither read nor write to it without the assistance of such software as the $49.95 MacDrive.

Rob Pegoraro attempts to untangle computing conundrums and errant electronics each week. Send questions to The Washington Post, 1150 15th St. NW, Washington, D.C. 20071 or robp@washpost.com. Visit http://voices.washingtonpost.com/fasterforward for his Faster Forward blog.

View all comments that have been posted about this article.

© 2009 The Washington Post Company