To avoid inconsistent data, respondents are, by default, prohibited from restarting a web survey that uses sample management. However, sometimes respondents might not finish a survey for legitimate reasons: for example, poor network connections; accidentally double‑clicking the survey start URL; or difficulty finding the original survey when using a mobile device. To enable respondents to restart a survey, you can do one of the following methods:

In most environments, you can use Method 1: Connect back to original instance of interview. This method relies on the new survey request coming in on the same interviewing engine as the initial request; this is usually the case, except in high-load scenarios or when the default load balancing script has been changed. In version 7.5.1 and later, the default load balancing script checks the IsCachedInterview so that existing interviews are load‑balanced to their original engine, and the respondent returns to the last page of an existing interview when a second start request is received for the same respondent.

If projects are likely to be cached on multiple engines, you can use Method 2: Multiple parallel instances in addition to Method 1. However, if a respondent uses multiple browsers, there might be inconsistent data until the transfer process resolves the data.

The ability to restart active survey applies only to projects that use sample management. When a respondent restarts a project without sample management, a new interview is always started.