Chapter 5. Frequently Asked Questions

Abstract

The final chapter in this user guide has frequently asked questions, which will hopefully help resolve any issues you have. I've also added a few that I thought might be helpful.

Table of Contents

Setup-related Questions
Runtime Questions
Post-recovery Questions
Troubleshooting Questions

Setup-related Questions

Q: Can I run DDRescue-GUI on Windows?
Q: On Windows, I get a message about the program not being from a verified publisher.
Q: On macOS, I get a message about Apple not being able to verify the program is free from malware.
Q: Why not use Windows drive letters?
Q: Why do I need to use a mapfile?
Q: What is "Direct Disk Access"?
Q: Why isn't Direct Disk Access available on Windows?
Q: Why is the read backwards option helpful?
Q: Can I recover to optical (CD/DVD/Bluray) drives?
Q: Can I run more than one instance of DDRescue-GUI at once?
Q: Can I restart DDRescue-GUI after aborting my recovery?
Q: What preset/settings should I use?
Q: MacOS: Where are the /dev/rdisk* devices?
Q: Can I use a domain mapfile to speed my recovery up with DDRescue-GUI?
Q: Can I use DDRescue-GUI to recover from encrypted volumes?

Q:

Can I run DDRescue-GUI on Windows?

A:

Yes, you can run DDRescue-GUI on Windows 7 or later.

Q:

On Windows, I get a message about the program not being from a verified publisher.

A:

Sadly, developer certificates for Windows are very expensive, especially for sole traders like me. That said, I will be looking into this so a release in the near future may not come with this warning.

For now, the clean bill of health shown by VirusTotal will hopefully alleviate any concerns you may have about malware.

Q:

On macOS, I get a message about Apple not being able to verify the program is free from malware.

A:

Sadly, it is expensive to be a member of the Apple Developer Program to get a certificate, especially for sole traders like me. That said, I will be looking into this so a release in the near future may not come with this warning. You can ignore the warning by right-clicking the program and then clicking open.

I will take this opportunity to say that it isn't very kind of Apple to mark everything that isn't signed with a paid certificate as malware, especially when there are very few extra checks done for signed packages.

For now, the clean bill of health shown by VirusTotal will hopefully alleviate any concerns you may have about malware.

Q:

Why not use Windows drive letters?

A:

Unfortunately, the compatibility layer used, Cygwin, does not support this. Instead, I have provided a way to determine the Linux device name for each drive letter (the Disk Information Window). If you're interested, you can read more about Cygwin at www.cygwin.org

NOTE: I have an idea for how to improve this, so a future release may more clearly indicate drive letters on Windows.

Q:

Why do I need to use a mapfile?

A:

There's are lots of reasons, and it really is very important. See the section called “Why should I use a mapfile?”.

Q:

What is "Direct Disk Access"?

A:

Mostly, you should just leave this on, because it usually makes it easier to read damaged drives and helps you recover more data. If you want to know how it works, see the section called “Direct Disk Access”.

Q:

Why isn't Direct Disk Access available on Windows?

A:

Direct Disk Access is a kernel level feature not supported by Windows. If you need this, you'll have to perform your recovery via Linux or macOS.

Q:

Why is the read backwards option helpful?

A:

If the very start of your disk is difficult to read, it may enable you to get most of the data more quickly. If you think your drive is about to stop working completely, this could help you a lot.

Q:

Can I recover to optical (CD/DVD/Bluray) drives?

A:

Unfortunately, no. This would be difficult to implement, and also writing to these drives is slow; if you think your source drive might be about to die, the last thing you want is to hold it up writing an optical disk.

You could recover to an image file, then use tools to split that file into CD/DVD sized chunks and write them, but that may not be helpful anyway; sometimes you need to repair filesystems and so on before you can read data. Reading disks like that would be difficult as well, and more suitable for a backup program to do.

Q:

Can I run more than one instance of DDRescue-GUI at once?

A:

As of DDRescue-GUI v2.1.0, you can now run multiple instances. However, aborting ddrescue for one recovery will currently abort all other recoveries as well - this feature is not complete yet. You may also experience system instability when reading from multiple damaged drives at once, so I can't really recommend this. Running multiple instances at once has not been tested on Windows.

Q:

Can I restart DDRescue-GUI after aborting my recovery?

A:

Absolutely, but only if you used a map file. Just make sure you have exactly the same input, output, and map file settings, and you should be good to go. You can safely change the settings in Settings Window, which allows you to try different approaches to get your data more quickly. See the section called “How can I resume or restart my recovery?”.

Q:

What preset/settings should I use?

A:

See the section called “Setting up for your recovery.” for the basics. If you want more details, have a look at the section called “The advanced options in the settings window”.

Q:

MacOS: Where are the /dev/rdisk* devices?

A:

They are intentionally hidden. If you want to use direct disk access, pick your device the usual way, and tick "Use Direct Disk Access" in the settings window.

Q:

Can I use a domain mapfile to speed my recovery up with DDRescue-GUI?

A:

At the time of writing, you can't. This is because DDRescue-GUI supports old versions of ddrescue that don't have that feature, and the process of making a domain mapfile is different for different filesystems; it would probably become complicated, and it would be hard to make a simple interface for this.

Nevertheless, I might implement this in a future release if there is demand for it.

Q:

Can I use DDRescue-GUI to recover from encrypted volumes?

A:

Possibly. On Linux, LUKS encryption doesn't work with DDRescue-GUI at the moment (you can't mount the output file), though other encryption methods may work, but I haven't tested the GUI with them. The same goes for MacOS encryption, so your mileage may vary; it may work, but is untested at the time of writing.

Quite probably, it will work, but you will be unable to mount your output file/device.