Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I am using Ubuntu 12.04 LTS 32 bit .. later I came to know that My Lappy has 64 bit processor ... so I downloaded Ubuntu 12.04 LTS 64 bit and wrote that image to DVD ... and tried to ( as i want to try dual boot ) ... when selected boot from DVD its giving " Error: Prefix not set " and a wierd screen ... then i had to reboot forcibly ... tried 4 times but couldnt install ... i checked the md5 and its matching ... Please help me how to install ubuntu 12.04 LTS 64bit .... I am able to install that in Virtual Matchine and its working fine ... please guide me how to install ...

Thanks in advance,

Ramakrishna G

share|improve this question
i even tried with downloading cdimage from precise alternate image and burn it to dvd ... and tried to install ... but same problem ... error:prefix not found... then a wierd screen appears ... please please help me what to do ... how can i install 64bit ubuntu on my laptop? – G Ramakrishna Jul 30 '12 at 17:47
up vote 1 down vote accepted

Its all wrong with a cyclic folder " ubuntu " which is shortcut created in the ISO ... because of that i couldnt install ubuntu 12.04 LTS 64 bit ... I have downloaded ISO master from software centre and deleted that that ubuntu folder and saved that iso in other location and burned it to DVD ... thats it ... Its all worked fine .. .now i am using it without any problem ...

If you have the same problem .. then install iso master in ubuntu and edit the iso file ...

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.