Check disk and dismounting

[Tharwatime]

I wish to run chkdsk q: /r, where q: is a USB drive which has data. The following message appears. Advice about how to proceed would be valued. Also, can a screen shot be put in the middel of a post? TIA.

 

[GokAy]

I guess some file is open. Dismount should be synonym to Safely Remove in this case. Yes or try the command right after Removing and re-plugging.