I know this thread is kinda old but I have had this problem for the past 2 days and being a total linux n00b it has been frustrating the hell outta me. No matter what I did I could not get yum to unlock. Finally I just deleted the yum.pid file and it solved my problem. Just thought I would post my experience.

kryznic yes posting to old threads is not a good idea
-- you get a bunch of -- please do not...--

but a search would turn up that running this in the terminal will solve most yum problems , and is recommended as the First thing to try


also a "yum.pid" leftover can be from a crash

I just tried the solution by John W:
Here's how I solved my problem:
1. Restart the computer.
2. Open terminal, then su - [Either su with or without -]
( your root password when asked )
yum clean all

I just figure I would use the search to find something that solved my issue rather than create another thread for a question I am sure has been documented numerous times. Many of the forums I frequent encourage searching, the age of the thread normally does not have a bearing on the resolution. Old or not this thread helped me fix my problem.

Awesome straight-forward answer
 

I was reading through all the thread and everyone was showing how to see the process, but when I got to this very last post and tried it, it worked like a charm.

Thanks for helping us newbies,.

yup, that is what I have had to do a few times, the yum.pid gets eternally locked. Not sure why, but haven't had it happen lately so maybe a fix came down in one of the bazillion updates I see daily lol.

Lots of responses here - but here's how I get around this issue. Its similar to other posts where one identifies the yum process/es that is holding the lock on yum and killing that PID/s.

NB: This can be dangerous especially if you kill the wrong PID by mistake.

tnX ..alot ..

Solution 1:
To remove the pid, please run command rm -f and follow with yum.pid path and [pid number]

[root@server /]# rm -f /var/run/yum.pid [insert pid]

Solution 2:
Find out what is the locking up yum by running:

[root@server /]# ps aux | grep yum

Please take note on the [pid number] of the process and run this command to kill the process:

[root@server /]# kill -9 [insert pid]

http://www.ehowstuff.com/how-to-reso...or-it-to-exit/

Ctrl + D logs you out of root and closes the terminal

if your gui software manager is open then yum will get locked don't run yum and gui software manager simultaneously

Use killall -9 safe_yum

Another app is currently holding the yum lock
 

i tried editing the file /var/run/yum.pid, deleted the contents, usually it's the pid that's locking yum, and saved it.
This solved the problem for me

well done guys :
just as a suggestion if you have a tick error.

1. login as root to the linux box
#su
your pass:

#init 3

login: root
your pass:

#startx

now go true to the terminal.

e.g ) #yum install update
Loaded plugins: langpacks, refresh-packagekit
Existing lock /var/run/yum.pid: another copy is running as pid 1232.
Another app is currently holding the yum lock; waiting for it to exit...
The other application is: PackageKit
Memory : 28 M RSS (356 MB VSZ)
Started: Sun Sep 28 10:30:23 2014 - 00:18 ago
State : Sleeping, pid: 1232

OK ! the PID has been notified at the end of the second line ((1232))

just use:
#kill 1232

be lucky.