Corrupt vmdk

[KCJones]

I have a virtual machine (server2003) that complains about disk error occasionally, otherwise works fine.

On checking the .vmdk it is corrupt, when I try and copy to another drive I get an io error.

I'm running the ESXi5.1 free version. How can I run the equivalent of fsck on the disk to see if it will fix it, it's version VMFS 5.

[continuum]

There is no tool like checkdisk for VMFS - there are only tools to check consistency but nothing that will help to fix problems.

Try to run
vmkfstools -i "existing.vmdk" "new.vmdk"

if you can do that without errors the new.vmdk ca be regarded as ok.

If a clone via vmkfstools is not possible - try to create a clone from inside the VM. Tools that can do that are for example VMware Converter, ddrescue,ghost ...
If this VM displays the error warning occasionally I would like to see a vmware.log from a run when the message was displayed