The automated fault-protection action was triggered about 11 p.m. Saturday on March 16, while operating on the B-side computer, one of its two main computers that are redundant to each other, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Monday.
It did not switch to the A-side computer, which was restored last week after a memory and is available as a backup if needed, NASA said.
JPL engineers said the rover is stable, healthy and in communication with controllers.
The safe-mode entry was initiated when a command file failed a size-check by the rover's protective software. Engineers said a software bug had appended an unrelated file to the file being checked, causing the mismatch.
"This is a very straightforward matter to deal with," JPL Curiosity project manager Richard Cook said. "We can just delete that file, which we don't need any more, and we know how to keep this from occurring in the future."
Curiosity's science observations have been on hold since a memory glitch on the A-side computer Feb. 27, which prompted controllers to command a swap to the B-side computer.
Cautiously bringing Curiosity out of safe mode status on the B-side is expected to take a couple of days, JPL said.