Services across Torbay and South Devon NHS are "starting to return to normal" after the Trust declared a "major incident" earlier on Monday (23 September).
A "critical" IT systems failure led to the cancellation of all routine surgery and outpatient appointments at Torbay Hospital. GP practices and all community sites within the NHS Trust have been affected.
People were warned to only attend Torbay Hospital if it is "critical" to do so.
Deputy Chief Executive Jane Viner has apologised for the disruption.
Torbay Hospital is extremely busy and we are operating at OPEL 4 –the highest level of escalation. We are cancelling all routine operations for today and ask people only to come to Torbay Hospital if it is critical that they do so.
Systems affected by the fault included clinical systems, emails, an telephones.
The Trust advised patients due to attend the Eye Clinic or Eye Theatre at Torbay Hospital to attend as usual unless they had been contacted by staff.
The group stressed IT staff had been working through the night to try and resolve the issue and restore services.
The Trust has said it is in "a period of recovery" and further updates could be expected on Monday afternoon.