Microsoft said recovery work on its major software services had made progress, with service conditions improving and the email backlog falling substantially toward normal levels. More than 20 products and services could still produce errors, while users continued to report undelivered meeting invitations and unresponsive web pages. Microsoft attributed part of the disruption to a core server process becoming unresponsive under excessive load, but said the root cause remained undetermined. It planned to publish further technical details after the disruption ended and said there was no evidence of malicious activity, though the investigation was ongoing.