Taiwan Semiconductor Manufacturing Company (TSMC) announced Saturday that a virus infected "a number of computer systems and fab tools." The company was quick to identify the issue, but different fabs were affected to varying degrees, which meant some were brought back online before others. TSMC said about 80% of affected machines were restored on August 5; the rest were expected to be up and running on August 6.

One day of lost productivity might not seem like much, but for companies operating on TSMC's scale, any delay is cause for concern. The company warned that it expects the issue to cause shipment delays and incur additional costs, resulting in an estimated 3% hit to its quarterly revenue. It plans to make up for missed shipments in the fourth quarter, however, and remains hopeful that it won't be too hurt by the incident.

TSMC said the virus' spread didn't result from a hack, per se, but rather from human error during the installation of a new tool. It explained:

"This virus outbreak occurred due to misoperation during the software installation process for a new tool, which caused a virus to spread once the tool was connected to the Company’s computer network. Data integrity and confidential information was not compromised. TSMC has taken actions to close this security gap and further strengthen security measures."

CNN reported that TSMC was affected by a variant of the WannaCry ransomware that garnered headline after headline in 2017. It's not clear if this variant of WannaCry actually sought ransom or if it merely wreaked havoc on TSMC's machines. CNN only said that the virus made the affected machines crash or get caught in a reboot cycle; TSMC doesn't believe any confidential data was compromised as part of the outbreak.

TSMC said most of its customers--which includes companies like Apple, Nvidia and Qualcomm--have been notified of the incident. (One would hope; it's not like the company's talking about a puddle in the break room here.) It's not clear how the incident might affect the release of upcoming iPhones, for example, or Nvidia's GPUs. But if Apple and Nvidia announce delays for those products, well, we'll have a good idea why.