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As per title, I wish to know if I can, after a successful 32bit setup and consequent software installations, update to a 64bit version.

I know how to partition (actually one of the solutions is to set /, /etc, /home, /var/www, and /opt as separate partitions) and I know that a clean install is way better than a dirty one, yet I would like to know if/how it's possible to do that.

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This is the same question, but shouldn't be marked as a duplicate, cause there are alternative answers here also: How do I upgrade from x86 to x64 without losing settings? – rubo77 Jun 20 '14 at 7:51
Similar question on U&L: – Wilf Nov 23 '15 at 22:05
up vote 56 down vote accepted

You will find a clean install a lot less hassle than any other unusual, obscure, unsupported method.

Your suggest of partitioning the config files, home directories, etc is probably the best idea, and it is possible to install the same packages on a clean install as on another install.

On the other hand, what you requested is possible, there is a little guide for Debian based systems but remember "this really is for professional-level sysadmins" and "this procedure is, in every possible respect, a bad idea. If it eats your firstborn, please don't come crying to me"... (so good luck)

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+1 to you. Not for the faint-of-heart... I was going to recommend backing up all config and data files that you care about (maybe even your apt logs), and doing a find-and-replace on your apt sources.list to point to the 64-bit versions. Then I read the tutorial mentioned and was quickly disabused of that notion... – gWaldo Oct 1 '10 at 17:52
What if I have no firstborn, does this mean the procedure is safer for me than others? ..... i kid, the question is: If you just got 32 bit working right, why do you want to go through hell just to save yourself backup/restore of data time + reinstallation time, in the end this method is not faster. Faster = backup, reinstall. Also less problems in the long run. – Dmitriy Likhten Oct 1 '10 at 18:48
Thanks a lot: eventually I backed up all my data, partitioned my disk and reinstalled. Now some hassle to restore DBs, webserver and some service is required, though. – dag729 Oct 3 '10 at 8:54
@dag729: Trust me, its a hassle to backup/restore, but less than the alternative. You only do 32 -> 64 in dire cases. Even the sysadmins here at work won't do that, they backup, wipe, install, much cleaner/safer. – Dmitriy Likhten Oct 13 '10 at 20:13

This might be a much more reasonable thing to do once the multiarch spec is implemented. -- currently postponed to 11.04, but keep in mind it's been postponed for about 6 releases now. That said, actual progress was made in 10.10, so maybe it'll happen this time.

Until then, don't bother. Backup your data, repartition if you want, and reinstall.

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Can't wait for the MultiArch to be implemented! – dag729 Oct 3 '10 at 8:52
I believe 11.10 does use multiarch now. – Christopher Kyle Horton Dec 21 '11 at 8:12
Suppose I'm a time traveller that is here ~5 years after your answer, is it "more reasonable" now? Or, still re-install? – Camilo Martin Apr 28 '15 at 21:21
It's now at least possible to forcibly manually install packages from other arches in a way that doesn't break apt. But no, you should just reinstall. – Scott Ritchie May 2 '15 at 2:26

No you can not upgrade from 32 bit to 64 bit. It has to be a clean (fresh) install

Before you do make sure that your system is capable of a 64bit operating system, and check the minimum requirement for Ubuntu 64. You can do so Here

The terms 32-bit and 64-bit refer to the way a computer's CPU, handles information. The 64-bit version handles large amounts of RAM much better than a 32-bit system. If you are running a 32-bit version of Ubuntu, you can only perform an upgrade to another 32-bit version of Ubuntu. Similarly, if you are running a 64-bit version of Ubuntu, you can only perform an upgrade to another 64-bit version of Ubuntu.

If you want to move from 32-bit Ubuntu to a 64-bit Ubuntu, you'll need to back up your files, do a clean install of 64-bit Ubuntu.

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You can now do this fairly easily with recent installers (at least with 13.10 which I just used). Boot into the 64-bit image DVD (or USB drive or whatever) and choose the first option to reinstall, keeping your personal files. This works even if you don't have a separate /home partition.

This will reinstall most of the system including apps, but it takes a list of your installed packages beforehand to reinstall them from repo, so as long as a package has a 64-bit version available to it at the time, you should end up with most of your apps when you reboot. In my experience a few didn't get installed - mainly those that had been installed through 3rd party repos such as Google Chrome - but it doesn't take long to install these manually afterwards.

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Can you share a source with instructions on how to do this / caveats? – isomorphismes Feb 28 '15 at 4:39
I checked this with 14.04 LTS and unfortunately, it can't be done anymore. For the gory details, see my answer below. – filofel Apr 24 at 18:47

It is possible to upgrade ubuntu 32bit to 64bit, it will have lots and lots of unwanted files, and you have to clean it manually. Truth is "HEADACHE".


What ever you do, first back-up your important data. Then go for research with os.

First try live-cd of 64bit. If it works go for fresh install, recommended.

Also there are some software, which are still 32bit. So to install 32bit software on a 64bit os, we need some backward processing.. these will also a bad thing.

Think for some time : whats your requirement, what you are going to do, next plan/work with 64bit os.

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What do you mean by "to install 32bit software on a 64bit os, we need some backward processing"? x86_64 is supposed to be like a superset of x86_32, so, things just work, don't they? – Camilo Martin Apr 28 '15 at 21:24

Your OS is still 32bit as you upgraded from a 32bit - see the answer in the comment for further information.

by the way is it possible for the coexistence of 32 bit Win and 64 bit Ubuntu?

Absolutely - it's called a dualboot - you would have the option at login to use either one.

Download and burn the 64 bit iso and boot with it, it will prompt you with various options - you would want to choose the Install alongside option.

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I just tried the solution suggested above by Nick (Oct 19'13): Using the Ubuntu 64-bit Live CD to do a 64-bit reinstall.
I used the Ubuntu 14.04.4 Live CD. But if the first option is indeed called a "reinstall", it more precisely appears as:

Erase Ubuntu 14.04.4 LTS and reinstall  
Warning: This will delete all your Ubuntu 14.04 programs, documents,
photos, music, and all other files.  

The two other options offered by the installer on the Live CD are:

  • Install alongside (dual boot option)
  • Erase disk and install Ubuntu

To be real sure, I tried with a test disk, and indeed, the first thing the "reinstall" option does is to reformat the existing ext4 partition. No luck.
So I'm afraid the "upgrade in-place to 64-bit" solution Nick suggested doesn't exist anymore in 14.04.
And BTW, Canonical, I hardly see the point for the installer having both the so-called "reinstall" option and the "Erase disk and install" one. Both seem to do about the same thing.

Too bad, since such an upgrade-to-64-bit-in-place option could have been real nice!

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Thanks to all for the various suggestions and recommendations. I considered all and then decided to simply reinstall Windows 10. This supports 64 bit and is what I originally had. Apparently (probably my error) I downloaded the Ubuntu 32bit version which would not work with my configuration. Now I can reinstall and do it right. Once again, many thanks to everyone who took the time to respond to my problem. Bill

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You need to do a fresh install with the 64bit version of Ubuntu. It is possible to have 32bit windows and 64bit Ubuntu, as long as they are not sharing the same disk or partition, for obvious reasons. Refer to the documentation for howto on dual-booting.

It is important that the CPU on the machine you're installing onto supports 64bit instruction set (which most modern CPUs should by now)

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Did you even bother to read the question? – dag729 Jan 3 '15 at 20:59

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