Hi. I have a Mid-2009 Macbook Pro 13". I was using Mavericks and decided to give El Capitan a try and at the same time to perform a clean install because my computer was running slow and I don't even remember when was the last time I did a clean install of the system. I was afraid that the new OS would not run properly and that my old apps would not be compatible so I decided to create a second partition on my 1TB harddrive and install it there. So far so good. The operative system was installed, I made it the Startup partition and I copied all the data from the previous Mavericks partition into the new El Capitan one. I then proceeded to try to delete my previous partition with Mavericks. I opened the Disk Utility and erased the partition. Then when I wanted to completely delete the partition and have just the partition with El Capitan I noticed that the "-" in Disk Utility was greyed out. I did not understand what was happening so I tried to just reduce the space of the empty Mavericks partition to the minimum, but instead of having now a small Mavericks partition with around 6GB and an El Capitan one with 994GB I got a third partition "Untitled" that also has the "-" greyed out. So now I have 3 partitions and I can'tt delete the 2 I don't need. Curiously the only partition where the "-" is not greyed out is exactly the one I want to keep. I was searching and found people with similar problems but somehow I can't find a straight forward answer on how to solve it. I am currently making a Time Machine backup of the El Capitan partition (I excluded from the backup the 2 others I don't need on the time Machine options) and thinking that I should just completely wipe the disk, reinstall El Capitan and restore everything from the Time Machine backup. Meanwhile can someone tell me if there is a possibility to delete these 2 partitions without wiping everything and restoring from Time Machine? Thank you in advance.