how to resize my bootcamp partition without deleting itit

Not possible within Disk Utility. You will likely need a third party alternative. I'd suggest searching for one that suits your needs.

To resize (or delete) an existing partition without losing data, you will need to use, for example, iPartition:

http://www.coriolis-systems.com/iPartition.php

Consider CampTune.

http://www.paragon-software.com/home/camptune/

Yesterday expanded my bootcamp partition from 50 up to 100 Gb using Mini Tool Partition Wizard Home Edition, a Freeware Windows Program after seeing this video: http://www.youtube.com/watch?v=WeKeawqxUa0

Note that I have OSX Mavericks, Steps are:

1) backup all your files (optional but strongly reccomended).

2) Using OSX Disk Utility resize MacintoshHD partition leaving unallocated space as much as you need to add to bootcamp partition.

3) Set Bootcamp as Boot Disk and restart the mac.

4) in Bootcamp with Windows running launch Mini Tool Partition and select the bootcamp partition.

5) Choose "expand" option in order to expand the partition using all the unallocated space.

6) The program prompt to you to restart the mac for apply the task, cause is not possible while the partition is mounted and windows running.

7) Restart the mac and then automatically Mini Tool Partition will do the job in a "graphic msdos like" form.

I was lucky and worked for me, I have a Late 2009 Mac Mini with MAVERICKS and a samsung 250Gb SSD Evo.

Hope this can help the community but decline any responsibility, do it at your own risk, you can use programs like winclone or camptune if you feel more comfortable with a pay app.

Fantastic solution - worked perfectly. Thanks!

You are welcome, I am glad it worked for you too. It is indeed a brilliant solution at no cost, I am continuing to use the computer without any problem with both windows and osx.

Thanks! Worked Great!

If you search through these forums, you'll find people who have had their bootcamp partition disappear when they do a major OS upgrade. Folks have posted that the culprit is doing what you've done above: decrease os x partition, boot into windows, increase windows partition size.

I can't find any evidence that the Mini Tool Parition Wizard software does or does not result in this situation, but there's enough talk out there that personally I'm going to just nuke my bootcamp partition and recreate it at a larger size. That seems the safest (if not also the most labor intensive) way to go.

Thanks for your reply, what you said is very important and everyone should take this into account before resizing bootcamp partition.

I did not know that there might be problems with a osx system update, but I had also read that even using camptune some users have had problems during resizing, so rather than spending money on a program that use once or twice I did a search and found that video of a boy who had used the procedure I posted and decided to risk.

People who read this thread would do well to read carefully the contribution of Michael Post1 before acting with Mini Tool Partition Wizard.

Thanks for posting this! You solved my problem.

I did follow the instructions on the YouTube video.

Warning.

Afterwards Windows will collect that allocated space.

Which is AWESOME!

But on the OS X side, it will show unallocated space still, and show the original sized

boot camp partition.

PLEASE do not click Verify or Repair Disk on that Partition.

I wanted OS X to see Windows for what it was.

In that process it corrupts the Boot Camp Partition.

So windows is GONE.

I think I am more sad about the 250 gigs of games I had.

It just takes so long to download each one in steam.

Best,

Joshua

https://discussions.apple.com/thread/4144252 <<-- Useful.

When you allocate new partitions etc, it will stop the windows booting in some cases.

This discussion will tell you how to rebuild the loader.

Thank you so, so much! I tried it and it was a big success!

Hi everyone, I resized my Boot Camp partition using the method from this thread, and then I read about the possible consequences, and opted to wipe that partition with Boot Camp Assistant and instead use Windows in a virtual machine. As far as I know, my MBP's partition table contains nothing strange—no remnants of the resize operation that could cause damage in conjunction with an OS X update later—but could anyone suggest a method to verify that this is the case? Thanks a bunch!

I followed Bonadventure's directions, and it toasted my Windows partition.

Now on boot, Windows complains that it can't read the boot configuration data, error 0xc0000225.

Don't attempt this procedure until you've made a backup with WinClone or otherwise, because I'm not the first person that this has happened to.