Q: "the last backup could not be completed"

Thanks donbarrett...your suggestion worked for me!!

Sadly, neither option here worked for me.

It would be useful if the error message was more helpful and identified why the backup had failed - I could at least then disable the offending app.

Worked like a charm.  Thanks!

Thank you for that! It worked wonders!

I have a question.  If you just do the iTunes backup, is it the same as backing it up to iCloud? I mean it will only sync when you click backup in itunes. But it is essentially the same correct?  Because I'm tired of stressing over this.  All I want is to make sure the backup works when I get the 5.

It will sync to iCloud by pressing "back up now" or when your iPhone is locked, plugged to power supply and wifi is available.

If backup was successful, you will see bottom "last back up at xxxx"

Cheers

Thanks...worked for me! 

First let me say I'm pretty much a novice about these things.  My iPad backed up perfectly.  My iPhone - not so much.  It also says "the last backup could not be completed".  According to my phone, it has never been backed up to iCloud.  According to itunes, it has each time I've tried to back up from the phone.  I suspect it says that in iTunes just because I clicked Back Up Now.

I've tried each of the suggestions above without success.  One question:  how much available space on the phone do you need?  In my general info it says Capacity is 13.7 GB.  Available is 4.2GB.  Is that enough and if I need more do I just delete apps?  Lots of questions, sorry.

im having the same problem. I've now noticed that if i turn off back ups from camera roll (even though it's my photos i'm trying to back up!) the phone will back up. i have loads of free space on the phone and even bought more as i thought this was the problem, but it didnt work. i have now managed to accidentally delete about 200 of my photos trying to fix this problem . I have backed the phone up twice manually today but according to the phone its never been backed up at all!

The specs require around 40 MB for space on the device for an icloud backup.  So you should be fine.

I've tried other suggestions but yours is different so I'm trying it.

When getting to the last step (5) the spinning wheel is going, message says Backing Up... and the estimated time is not showing.  The progress bar is stuck at around 3-5% (questimate).

Now it's showing About 7 hours remaining.  (About 8 minutes into the backup process.)

After more than 12 minutes into the process, the backup gives up and reports "The last backup could not be completed."  And yet, the "incompete" backup shows 820.7 MB of data, so a lot of data has been transferred.

Oh well, back to the drawing board!

(I have lots of free space in iCloud and over 10GB free on my iPad.  I'm able to move Pages documents around using both my mac and iPad, so the connection to iCloud from the iPad is working.

This helped to solve my problem.

Thanks.

I was having the same problem after Jailbreaking my iPhone4, I just tried richpharm's method of turning off iCloud backup then deleating the previous backup and it worked like a champ. When the icloud backup initally started it said about 17 minutes remaining, after only about 3-4 minutes iCloud backed up and was complete. I'm running a second backup as I type and now it's only taking a few seconds to back up so I'm guessing it was succesful.

It even backed up to iCloud when I unplugged it from my laptop and ran a manual back up into iCloud settings. So looks like all is good thanks. many Kudo's

Several things I want to point out...

You say you have loads of free space on the phone and even bought more..   You can't add more storage on your iphone, the amount you have is what you'll always have.  What you probably did was buy more storage on icloud, but this is not the same thing as memory on the device.

About photos...

You should be importing all pics taken with the iphone to your computer regularly as you would with any digital camera. 

iOS: Importing personal photos and videos from iOS devices to your computer

To richpharm

Thank you, thank you, thank you!

My iPhone 4S has never been able to sync wirelessly to iCloud, would only do it whilst in iTunes. I was continually getting messages to tell me that I hadn't backed up to iCloud in XX weeks. I tried all other suggestions such as "Delete backup" and try again, "reset network settings" and was considering deleting my iCloud account until I came across your solution.

And it just worked...again thank you.

Edit: Clarity