Students scheduled to take the MCAs, the statewide standardized tests, on Tuesday and Wednesday mornings experienced a setback when some were unable to log into the online system.

On Tuesday, a server at Pearson crashed at 9:30 a.m. Representatives from Pearson, the test provider, said students who had already begun testing weren't interrupted, but the crash caused problems for districts across the state.

"For us yesterday, we basically lost a complete day of testing," said Jason Molesky, director of technology and data for the Lakeville district.

State officials said they weren't sure how many students were affected. The problem was resolved by noon.

"We are so tightly scheduled," said Dave Orlowsky, Shakopee's data and testing administrator. "Because it's all online and there's so many students, one delay could really mess us up."

On Wednesday morning, the same issue resurfaced, though for only for five-minute periods, according to Josh Collins, spokesman for the Minnesota Department of Education.

Multiple districts, including Lakeville and Shakopee, again reported problems by mid-morning. Others, like Farmington and Burnsville-Eagan-Savage, hadn't noticed any glitches, representatives said.

The Lakeville students most affected by Tuesday's crash were Link12 students, who attend school online. They made a special trip to Lakeville to take the MCAs and were unable to test, Molesky said.

Districts can schedule the MCAs, or Minnesota Comprehensive Assessments, during a window that lasts from late March to early May. Many districts cluster them in mid-April.

In 2013, there were significant computer issues that affected students' ability to take the MCAs. The vendor providing the test then was the American Institutes for Research, or AIR. This is the first year that the state has used Pearson as a vendor.