Solving the Backblaze “Permission Denied” Restore Error

For many years, downloading backups from the Internet backup service Backblaze required using a slow, clunky, Web-based interface. It’s still available, and you can also request a hard drive with your files, but that’s worthwhile only if you’re restoring many gigabytes or more of data—see “Backblaze Raises Its Fully Refundable Price for Restoration Drives,” 18 July 2024.

However, in September 2023, Backblaze introduced the Backblaze Restore app with Backblaze version 9.0. It’s a native Mac app that provides a simple but effective interface for restoring files directly to your Mac. You can restore files in place, skipping or overwriting identical files in the original location, or you can choose a specific download location.

The annoying part of using Backblaze Restore is that it can take a long time to retrieve the file list—over two and a half minutes for my backups. I always end up going off to do something else while it loads. Wait too long, and your session times out, forcing you to log in and retrieve the file list again. Click the View Restore Progress button to see what that does, and it has to retrieve the file list again. Want to restore a second file after the first? Retrieve the file list one more time. Ideally, Backblaze would cache the file list in the background, perhaps once per day, so that Backblaze Restore could quickly download only changes when it launches.

Once you have a file list loaded, you can navigate the hierarchy, select the files you want to restore, and click the Restore button. The restoration performance is excellent; a 1 GB file downloaded in about 30 seconds over my 300 Mbps connection.

That is, assuming it works. When writing the earlier article, I wanted to test performance, so I triggered a restore, only to be met with a dire-sounding error about how something went terribly wrong. (Not just wrong, but “terribly” wrong—just what you want to see when dealing with a possible data loss situation!) Retrying made no difference.

Backblaze Restore provides quick access to the logs, which revealed a permission problem that prevented the creation of a temporary directory to hold the downloaded files. Without that directory, everything else failed.

Since I was having an email conversation with Backblaze’s Yev Pusin about the restoration drives anyway, I asked him about the error. He quickly relayed a suggestion from support to check all permissions on the directory in the highlighted text above to see if they were read/write. Indeed, they weren’t. In the Finder’s Info window, they showed up as Custom, and checking at the command line revealed that all three were missing execute permissions: drw-rw-rw-

Once I changed all three to Read & Write in the Finder’s Info window (only the first one is actually necessary), my subsequent restore worked perfectly. Yev said that Backblaze support had received a few other reports of this, and with mine as a nudge, he got information about this added to Backblaze’s support documentation. All’s well that ends well, and anyone who experiences this problem in the future should be able to find the solution quickly.