Clark was picked to fill the post in 2016 after Mike Brown left, again abruptly. His exit, on Thursday, saw the company's shares plummet by 15%, lowering its value by more than US$2 billion.
The departure of Clark came after Symantec, one of the bigger security firms in the US, reported poor sales for the fourth quarter of fiscal 2019, though profits were bolstered by expenses being cut.
Sale fell 1.7% to US$1.19 billion for the quarter; analysts had pegged in a figure of US$1.21 billion.
Symantec, which is being investigated by the Securities and Exchange Commission over accounting irregularities, also faces a lawsuit from shareholder James Felix, who claims its top executives massaged financial figures.
Regarding Clark's sudden exit, Symantec chairman Daniel Schulman said in a statement: "Symantec has a significant opportunity to further enhance shareholder value by continuing to build on the leadership and momentum of both our enterprise and consumer cyber safety segments.
"As we enter into a new financial year, Greg and the board agreed that now is the right time to transition leadership, and we are confident in Rick’s ability to drive the company forward while we work to identify a permanent CEO.”
He added: “Rick is a highly-regarded technology executive with a track record in enterprise computing solutions, and decades of experience leading public companies in the semiconductor and systems industries.
"His years of relevant leadership experience coupled with his familiarity with our organisation make him a natural fit for the Interim CEO role and will allow him to seamlessly take on the responsibilities.”