In her own words:

The recount has uncovered significant and widespread errors and anomalies in the securing of ballots and recording of votes on election day. There have been changes to vote totals in every county due to miscounted or missing votes.
Many bags of ballots have been found to be essentially unsealed or ripped to the extent that ballot security is compromised. A stack of ballots, unbagged, was found in a clerk’s office. Ballots were found in voting machines where they had been left. Seal numbers on ballot bags and tags were not recorded in the inspector’s reports, creating doubt that the bags were properly sealed on election night.
Touchscreen voting machine tapes were missing votes, or worse, were entirely blank and had to be reproduced from machine memory to allow a recount of the vote.
The most widespread and systemic errors and anomalies have been discovered in Waukesha County. That county was already under a cloud, and this recount has revealed more questions about elections practices there.