update

[Hilda1912+]

Error message: the archive file is corrupt, truncated or archive parts are missing

[AMurray]

More information please. What are you trying to do?

If migrating from 2.5.x to 3.x then please see viewtopic.php?f=710&t=793171.

It's could be a corrupted download (as suggested by the error message).

[Webdongle]

What are you updating and how are you updating it ?

[Hilda1912+]

What are you updating and how are you updating it ?

I was trying add to add an extension to my Joomla 2.5.28, but the Checkfront link would not let me paste to me computer. So it was suggested that I update to Joomla 3 That is when I got the error message. I am not a programmer, I just use the site and make few updates to our website.
I am trying to follow the instructions that someone has sent but I am very confused by the checking to see if any extensions I have are compatible with 3.x. I am so frustrated as I have trying to get this set up for over two weeks

[Webdongle]

Who sent you the instructions?

[AMurray]

I don't know what "checkfront" is.....on google searching, it comes up with an online booking system.... nothing to do with Joomla.

In checking for "compatibility" all that is saying, is to obtain the extensions (or similar equivalents) currently used in 2.5.x and get the version that will work with Joomla 3.

Again, just follow the steps Leo has posted in his Migration guide: viewtopic.php?f=710&t=793171.

Just be sure you make a backup of your site, before attempting any major system change like this.