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LimeSurvey version:  LimeSurvey Community Edition   Version 6.10.0+250106 
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Survey theme/template: Minimal Template
==================Hi,
I’ve set up a survey using tokens, and unfortunately, the person administering it at one of the schools handed out multiple copies of the same token (#177, as shown in the attached image), instead of distributing the unique tokens I had provided. As a result, although everyone was able to start the survey, only one person was able to complete it.Is there any way to prevent others from accessing the survey once someone has already proceeded to page one, so that this doesn't happen again?

Not that I know of.

The token only gets invalidaded, when someone has completed the survey.

Maybe there is a way via the stats plugin, not sure if you can access open ended questions, then you could check the token against other tokens (probably must change the approach a bit and save the token in a hidden question or something).

Ok, I expected as much. Thanks for the reply holch!