Re: Lightroom catalog cannot be opened because (DxO) already has it opened

Rob,

Just to close this thread and help anyone else who may have encountered the error, here is what the DxO support Team says:

Hello Michael,

We are aware of a similar problem with Lightroom 5.5, and it may also apply to Lightroom CC:

See this link for details:
  http://feedback.photoshop.com/photoshop_family/topics/lr_5_5_dxo_export_now_pops_up_warnin g_window_after_lr_5_5_upgrade

A workaround is to reinstall Lightroom downloaded from Adobe website (not from Creative Cloud application manager).

Let me know if this works for you.

Thank you

Best regards,

DxO Labs Support Team

And it worked!