All Things Digital

There’s no other major item most of us own that is as confusing, unpredictable and unreliable as our personal computers. Everybody has questions about them, and we aim to help.

Here are a few questions about computers I’ve received recently from people like you, and my answers. I have edited and restated the questions a bit, for readability. This week my mailbox contained questions about Windows Vista complaints, using antivirus software when running Windows on a Mac, and transferring large files.

In various past columns, you have complained that Windows Vista boots slowly and that it is incompatible with some software and hardware. Is this situation improving?

Microsoft claims that neither complaint affects most users, and that the minority of cases where they do is being whittled down steadily. I expect that the incompatibility issues, at least, will diminish over time. But I am still receiving reader complaints about incompatibility, so I have to assume that this issue remains real, at least for some people. The slow start-up issue will be harder to cure, as it involves factors like add-on trial software, called craplets, that are beyond Microsoft’s control. Officials at a number of Windows PC makers tell me they are beginning to get the message that people hate craplets. But I am still observing slow boot times in new Vista PCs I test and still see plenty of craplets.

If I run Windows on a Mac, do I need two copies of antivirus software, one to run in the Windows environment, and one to run in the Mac operating system?

You need only one copy, to run in the Windows environment. Macs have essentially no virus problem, and thus don’t need antivirus software. However, some Mac users install it to be extra safe, or to kill viruses that they fear might be passed on via email or over networks to people using Windows.

In last week’s Mailbox, you advised someone that he could copy a 25-gigabyte file from a Mac to a Windows PC using an external hard disk formatted for the Windows FAT file system. But I believe that won’t work. Do you have another solution?

You are correct that I erred. I forgot that the FAT file system, the only Windows format to which Macs can save files, is limited to file sizes of up to 4 gigabytes. This is almost never a problem, except in the case of extraordinarily large files. I did offer several alternate solutions last week, including using a network or cable transfer. But here’s another: You can use a Mac-formatted external hard disk, or a Mac-formatted iPod acting as a hard disk, to transfer the file, provided you have installed on the Windows PC special software that allows Windows to read Mac-formatted disks. This software is called MacDrive, costs $50, and can be purchased at mediafour.com.

You can find Mossberg’s Mailbox, and my other columns, online free of charge at the new All Things Digital Web site, http://walt.allthingsd.com.

Write to Walter S. Mossberg at mossberg@wsj.com