ubiquity crashed with TypeError in partman_dialog(): 'NoneType' object is not subscriptable

Could you try booting the cd, pressing F6 and selecting nodmraid option? Thanks in advance.

This may be the same bug as bug 1062625.

The reason why you cannot edit the partition, is because RAID capable controller got detected and activated. You can boot with nodmraid option to work around that.

The crash, which was probably produced by double clicking on the entries, should be now fixed and that is bug 1057690.

[Expired for ubiquity (Ubuntu) because there has been no activity for 60 days.]

Asus X502CA, nodmraid didn't change anything.
Ubiquity 2.15.26

This is critical, I cannot install using Lubuntu 13.10 LiveUSB.

It happens when trying to install 14.04 LTS using multibootusb.
HP Elitebook 850 G1, 1TB HDD, 32GB Intel SRT cache.
Booting to live works ok.

14.10 doesn't boot due to other problems with syslinux.

I also have this problem. I have a system using Windows 8.1 that I want to convert to Ubuntu.

No devices are listed in the "Installation Type" screen. I have tried the "nodmraid" option and still have the problem.

Booting using CD trying to install Ubuntu 14.10. Using "Test Ubuntu" loads Ubuntu correctly.

Ubuiquty 2.20.0

Computer : HP Pavilion Elite HPE

I'm also having the same issue installing 14.04. I'm booting via USB.

I also ran into this problem (Mint 17.1 64bit Mate live DVD, single core AMD 64 bit processor 4gig RAM).
nodmraid boot option did not fix it (before and after --)
nodmraid option to ubiquity did not fix it (ubiquity refused to run)

I'm not an expert on this, but there are software and hardware RAID controllers and my Windows may actually use something that is technically RAID.

Make a backup. A good habit to get into. I keep a few large USB drives for this. Move your large files (videos, ISO's, etc.) off to the backup drive and use a clonezilla live CD to back up your whole hard drive. I go a step farther after that and use gparted live CD to shrink my older OS's because they won't be used much any more and make another backup after that.

If you are not actually running a RAID setup then one work around listed elsewhere is to erase the RAID metadata. I could not find any statement that said that was always perfectly safe (I suspect that it is perfectly safe because the metadata must pass strong checksum requirements). Use this from a terminal prompt to find which of your drives have RAID on them:
  sudo dmraid -r -c

Then use this to erase dmraid metadata (replace /dev/sda with something else as needed):
  sudo dmraid -r -E /dev/sda

The previous is probably the best way for most people, but I was afraid of borking my Windows install as it was not my computer and I didn't know if it might have had software RAID in Windows.

Of course if you are simply reusing an old drive and just want to completely erase everything that is on it you can just wipe the whole thing with dd or ddrescue or dd_rescue and that will get rid of any RAID signatures.

As another option that doesn't erase the RAID metadata, I worked around the problem by starting the live DVD normally, starting a terminal and entering:
  sudo apt-get purge dmraid
then running the Linux installer without rebooting in between.

Note that this only temporarily removes dmraid from the live DVD environment. It is back again after rebooting the live DVD.

The new installed bootloader did not include my other operating systems because of the same dmraid issues, so after booting the newly installed Linux OS I had to bring up a terminal and enter these:
  sudo apt-get purge dmraid
  sudo update-grub

Also note that your grub configuration will have 'nodmraid' configured in /etc/default/grub so you won't be able to use RAID without changing that and running sudo update-grub, but most newbies don't need Linux RAID.

I have the same issue trying to install Ubuntu 18.04 and 17.10.1 on my Dell XPS 15 running windows 10.

I'm experiencing this also while attempting to install Ubuntu 18.04!!!

Also here installing 20.04.3 and 21.04... sad.