MUTLIPLE STEP FILES OPEN IN A SINGLE STEP FILE

Hello all,

One of my client whenever he tries to open a step file after importing it comes along with an another step or iges file gets opend along with that so they've reinstalled NX and it was working fine, again after a few months he started getting this issue.
Can anyone suggest me only reinstallation is we have to do even though I guess it's not a std solution or any other methods to resolve this!

Thanks in advance