Image source, David BurchellImage caption,
David criticised Abbott for not "acting as quickly as they could have done" and said he was considering using a rival product
A popular app which helps diabetics check their blood sugar has been restored after issues.
An update had caused it to stop working on some Apple devices, causing distress to those depending on it for their glucose monitoring.
The manufacturer said a new version of the FreeStyle LibreLink app is now available to download which fixes the problems.
Abbott said people should upgrade to the latest version as soon as possible.
"We appreciate the patience while we fixed the issue and sincerely apologise for the inconvenience this caused," the company said in a statement to the BBC.
Users wear a small sensor as a patch on their arm or belly, which sends data to an app. The company claims to be the top sensor-based glucose monitoring system used worldwide.
The NHS says there are 200,000 people using these types of sensors in the UK.
On Friday there was a backlash online from people who rely on the FreeStyle LibreLink app for their wellbeing.
David Burchell, who has type 1 diabetes, had told the BBC it was "very scary".
"This equipment is supposed to save your life," he said on Friday. "I woke up yesterday morning, went to check my sensor thing and basically it broke, just showing a white screen and I had a panic."
He said Abbott had told him to delete and reinstall the app, but the firm had taken it off the App Store.
It meant he was left without an active test and had to rely on fingerprint testing, which he called "a nightmare".
People without these sensors have to resort to taking between four and 10 finger-prick tests per day to monitor their glucose levels.
What is the app?
The LibreLink app, developed by Abbott, connects to a continuous glucose monitor (CGM) - a white disc covering a needle inserted under the skin of the user, typically in the arm or belly.
People with Type 1 diabetes use the CGM to monitor their blood glucose levels - or blood sugar - around the clock, meaning they do not have to continuously take blood samples by pricking their fingers for readings.
By monitoring glucose levels in real time, people can make better-informed decisions about when to eat or exercise.
Critically, it can also alert the user or their family members when their blood sugar level is too low or too high.
The problems started after one of Abbott's CGMs stopped interacting with the LibreLink app of some Apple users.
Abbott said an update to the app had caused it to stop working for some users altogether, leaving them unable to monitor their blood sugar levels.
People without these sensors have to resort to taking between four and 10 finger-prick tests per day to monitor their levels.