[dawiz]

I can't access the unlock screen for my 9550...doesn't matter how many times I repeat that process and type MEPD nothing appears! Has anyone encounter this problem as well?

[JSanders]

Are you typing MEPD on the SIM card screen?

...following the directions stated here: How do I unlock my BlackBerry? - BlackBerryFAQ

[dawiz]

Yes I did. On numerous occasions too. It doesn't respond at all.

[Motorcycle Mama]

Try holding the SHIFT key down while you type the letters.

[dawiz]

Still no success!

[JSanders]

Is the device previously unlocked?
Any other known screen issues on that device?

[Pendro]

When I unlocked my 9550 had the same issue, couldn't access to the MEPD scrren, but on the sim card scrren typed MEP2 and enter directly to the enter mep code screen.