I can't believe this hasn't been answered yet. I also have this problem with my 3GS. I tried to delete my apps and music to balance out all the space that "other" is taking up (all of that used to be free space btw) and it won't let me sync my phone! Not only that, but I can't compose any emails =( I took a screenshot to illustrate the problem:
Last night i synced my mum's iphone on my laptop to update to the new OS 4.2 - It took about 40 minutes to back up then restored and reset.
After this is said restore from back up .... with a list.
The list didn't contain my mums backup only my previous backups on my account and my mums apple account no longer exists not only in itunes but all together.
I have been through the hard drive on my back and there is no data anywhere which shows the time and backup of my mums iphone.
The iphone is completely wiped and the apple account no longer exists, can someone help me and tell me if there is a way i can get the data back? i have used the iphone back up extractor and it isn't there - it must be somewhere as it took forever to backup.
i also just got this issue,
but what fixed it for me was doing the following,
connect the iphone run itunes and click transfer purchases,
then sync, this shortened the size of other by 2gb,
eject iphone close itunes,
connect too 2nd usb port, open itunes and redo the steps,
this time over 10gb of other went and now the other size is down to 1.41gb,
which is about right considering, itunes video,imovies videos and gps data...
I have a similar issue in which by selecting just one photo makes my iPhone go over capacity.
In the content and space available bar at the bottom of iTunes, it shows that my iPhone has 4.6GB free. However, when I try to add photos in the Photos tab, even checking just one photo makes it go over capacity by 0.1 or 0.2 GB!
How can this be?
Try Checking and unchecking different options on the summary page.
I checked and then unchecked "Sync only checked songs" and it shrunk a little.
I unchecked and checked Open iTunes when this iPhone..." and it suddenly went from 4.8GB to .78GB
Someone else apparently had luck with "Manually manage music..."
So I'd suggest checking and unchecking everything until something hopefully works.
I had the same problem (with a 3GS). After the restore that occurred with the system upgrade, I ended up with something like 9GB as "Other", which was pushing me over capacity.
Here's what worked for me:
1. I went to Music and unchecked a playlist that was about 10GB of music. This meant that I was no longer over capacity (at least according to the status bar).
2. I also chose to override the phone's Contacts with the Contacts on my desktop. (This is probably unrelated – I did it only because I'd had some conflicts show up during the upgrade – but I'm mentioning it in case it had an effect on the end result.)
3. Then I clicked Apply and the phone synced.
4. Result: 1.04GB of "Other", which is about what I'm used to.
5. I went back into Music, checked the 10GB playlist and 1259 tracks were returned to my phone on the next sync.
When updating to ios5 the phone stores all your previous data on the phone and builds a new operating system on the remaning spce. If you have more than half of the total capacity filled when you update, the new system won't fit. The solution is to sync without your music (any large data bulk will surfiste). After the sync has completed the 'other' portion, which is the old data, will have disappeared. Now you can sync your music.