LR odd error

[Kirk Gittings]

I worked on LR all day yesterday and came back today to do the same. I now get this error which I have never seen before. Trouble is there is nothing else open using that cataloge nor is PS or Bridge open. rebooting doesn't help and there is nothing in Task Manager that would indicate anything else running that might create this. Any thoughts. W7 64 and Lightroom 3.6 64 bit.

[johnbeardy]

In the folder containing the catalogue, look for any small files with names like journal or lock. I''ve seen cases where these haven't been deleted properly when LR closed and one or other may be to blame.