iOS 11 - connecting to Structure sensor takes longer + sensor doesn't connect after app was backgrounded


We noticed with iOS 11 that the time to connect to the Structure sensor takes longer than with previous versions of iOS. Furthermore, if I hit the home button i.e. background the app, and run the app again, then the sensor doesn’t connect unless I reattach the lightning cable. Debugging this issue ‘STSensorControllerInitStatusSensorNotFound’ error is thrown.

Would appreciate if someone can help with explaining why the sensor takes longer to connect ca. >3 seconds and if the sensor can stay connected when the app is in the background.

iPad Pro 10.5 Alignment Problem
Ipad camera no longer working

We have heard reports from other customers of this too. It seems that with the iOS 11 update, Apple has changed a number things that now makes accessories connected through the Lightning Port take longer to be seen by the iOS device.

It seems that updating to iOS 11.1 has solved many of the issues these customers were having with the new update.

There are other forum posts that highlight this and other issues customers have reported with iOS 11 that I would urge you to check out:


Hi Anthony,
we don’t experience any exceptions or crash it only takes longer and doesn’t reconnect when app was backgrounded hitting the home button.

Just tested with iOS 11.1 but the issue remains.

By the way, we experienced the same behavior with Structure and Scanner app.



Hi, Anthony:

Any fix for this bug: backgrounded app stuck in “Please connect Structor sensor” when it is waked up

I noticed
in this situation, the latest release Canvas app shows
“Please connect Structure sensor”
plus below message
(if the sensor is connected, please unplug and plug back the cable)




We have seen this issue with certain versions of iOS 11. We are working on isolating the bug and making a fix. Unfortunately, the issue seems to stem from how iOS 11 deals with accessories plugged in through the Lightning Port.

Device disconnect when starting the app

Another data point - iOS 11.2.5 on iPad Pro 10.5 still experiencing the “Please connect Structure Sensor” problem…