What happens to a review if the DRS technology fails?

If some or all of the technology is unavailable or fails, the third umpire tells the on-field umpire and still passes on whatever facts can be worked out from the replays and technology that are working. The on-field umpire then decides.

Is the review lost? A review marked "Unsuccessful" can be reinstated by the ICC Match Referee, at their sole discretion, if it couldn't be properly completed because the technology failed. The decision is final. A review is not reinstated if:

• the correct decision could still have been made with the other technology available, or
• the technology worked as intended but the evidence was simply inconclusive.

If the third umpire can't decide with a high degree of confidence that the decision should change, they report the replays as inconclusive and the on-field decision stands. The third umpire doesn't give likelihoods or percentages.

For an on-field umpire's own referral, a white light (where available) shows that third umpire reviews are temporarily unavailable, and the on-field umpire makes the decision.