The rover put itself into a precautionary safe standby mode on July 2.
After investigating why the rover put itself into a safe mode, Nasa's engineers said that the most likely cause was a software mismatch in one mode of how image data are transferred on board.
Science activity planning for the rover is avoiding use of that mode which involves writing images from some cameras' memories into files on the rover's main computer.
Alternate means are available for handling and transmitting all image data.
Curiosity was now communicating with ground controllers and was stable. The rover ceased most activities other than keeping itself healthy and following a prescribed sequence for resuming communications.
Curiosity has entered safe mode three times previously, all during 2013.
The rover landed in Mars' Gale Crater and has been exploring the area since August 2012.
During its first year on Mars, the mission achieved its goal by determining that, more than three billion years ago, the region offered fresh-water lakes and rivers with environmental conditions well-suited to supporting microbial life, if life has ever existed on Mars.
In continuing investigations, the mission is learning more about the ancient wet environments and how and when they evolved to drier and less habitable conditions.
Recently, the US space agency said it was planning to drive the Curiosity Rover towards water sites on the Martian surface to further investigate the long, seasonally changing dark streaks briny water in the hope of finding evidence of life.