Can a buyer waive a condition they were supposed to benefit from and still close?

Generally, yes — a closing condition that exists purely for the buyer's benefit can usually be waived by the buyer alone, letting the deal close even though that specific condition wasn't technically satisfied. This is a standard, useful piece of flexibility: a buyer might decide a minor unsatisfied condition isn't worth blowing up an otherwise good deal over, and waiving it lets closing proceed without needing the seller's agreement to that specific point.

The nuance is in confirming the condition really was for the buyer's benefit alone, and not something that also protects the seller or a third party, since waiving a mutual condition may need agreement from whoever else it protects. Purchase agreements often address this directly with a clause stating which conditions are waivable, by whom, and whether a waiver has to be in writing to count — details that matter if a dispute later arises about whether an informal waiver actually happened.

Waiving a condition doesn't necessarily give up related rights, like an indemnity claim for a known problem, unless the agreement's sandbagging language says otherwise — that's a separate question worth checking before you close on a known issue.