One hopes that writer-director Richard Curtis doesn’t think he was doing anything original with this time-travel romantic comedy. Even the title of the new effort from the creator of “Love, Actually” is a sad cliché, but the whole plot treads the same territory as “Somewhere in Time,” “The Lake House” and “The Time Traveler’s Wife,” and its mixture of whimsy and mawkishness is familiar, too. Watching “About Time” brings a strong feeling of déjà vu, and not just in that cinematic “Groundhog Day” sense (a far more enjoyable movie, by the way).

The focus of the plot is Tim (Domhnall Gleeson), a klutzy young fellow whose befuddled dad (Bill Nighy) informs the lad on his twenty-first birthday that the men in their family are endowed with the power to travel through time simply by enclosing themselves in a dark place and concentrating. But the ability is limited to returning to moments you’ve previously experienced yourself, merely to relive them or, if necessary, to alter them for the better.

Tim immediately seizes on the opportunity to redo some of his more embarrassing faux pas, especially those involving his ineptitude with girls. But after failing in his attempt to woo his sister’s friend (Margot Robbie), he largely abandons the game, instead going off to London to begin his apprenticeship in the law, and moving in with his father’s friend Harry (Tom Hollander)—a curious living arrangement that seems designed merely to introduce in the playwright an acerbic character who can deliver a string of comically cynical remarks.

In any event, it isn’t long before Tim encounters Mary (Rachel McAdams) in a typically oh-so-cute meeting in one of those restaurants that serve customers completely in the dark. It’s love at first non-sight, but unhappily Tim soon finds that he has to relive that night in order to save Harry from a disastrous professional embarrassment, and in consequence the whole episode with Mary is excised from history. That requires him to arrange a whole new scenario for them to meet, which leads to his smoothly removing her from a relationship with another possible suitor and linking up with her romantically.

That’s not the first time that Tim uses his ability—which remains unknown to Mary—to keep their happiness going into marriage and family life. But he employs it to address other needs as well, in particular crises involving his troubled sister Kit Kat (Lydia Wilson), whose habit of acting out sends her into a downward emotional spiral and threatens her safety. And the problem is that every change he makes in the past has unforeseen consequences, bringing the realization that even a power such as the one he possesses can’t protect you from sadness and loss.

There are some charming moments in “About Time,” most involving not Tim and Mary but Tim and his dithering father, who, as played by the always watchable Nighy, is easily the most endearing figure here. But most viewers will enjoy Hollander’s caustic comments, especially since they add some edge to the prevailing blandness and crass sentimentality, and there’s an amusing digression involving the performance of a scene from Harry’s new play by Richard Grant and the late Richard Griffiths, which could be better written but still gives one the opportunity to savor these two old hands’ skill at playing off one another.

On the other hand, one has to put up with a string of bits involving Tim’s uncle D (Richard Cordery), an amiable but eccentric fellow whose extreme forgetfulness is surely a sign of mental disability—a situation that’s treated as almost a public service message for thoughtfulness to those less fortunate. And then there’s all the material surrounding Kit Kat, a flawed girl who’s apparently intended to touch our hearts but is actually as irritating as one might expect any character with that nickname to be.

“About Time” looks lovely, with the English locales given a glow by cinematographer John Guleserian that’s clearly meant to feel magical. Meanwhile Gleeson succeeds in reminding us of the young Hugh Grant, which is what’s obviously needed here, and McAdams makes a pretty partner for him. Hollander seizes every waspish opportunity Curtis affords him, as Cordery does every chance to look lovably lost, but poor Wilson can do little with the impossible-to-like Kit Kat. Nick Laird-Clowes’ score is not only syrupy but makes the mistake of employing Arvo Part’s “Spiegel im Spiegel,” which has appeared in so many films and trailers by now that it’s become an aural cliché.

In the end Curtis has a point to make, but it’s no more than the banal observation that one should savor every moment in life and not take things—and people—for granted. A nice sentiment, to be sure, but hardly one that exudes originality—instead it reeks of something else, especially when at more than two hours the movie is way overlong. When this schmaltzy, brutally manipulative dramedy finally grinds to a halt, it’s you who’ll probably be saying “It’s about time.”