This is from my understanding of California Landlord Tenant rules, and should not, in any way to be construed as legal advice, always talk to someone in your area with the ability to advise you legally.But as far as I understand, when it was explained to me, the fact that you signed the lease is the important part. I believe, the fact that the landlord didnu2019t sign a form they filled in and/or created, and then presented you for your signature, kind of implies, a level of consent on the part of the landlord. Besides that, they can simply sign the lease & thereby make it official & binding, at any time.If, when presented the lease, you signed & dated as the lessee, you agreed to the terms in the lease, as presented to you, by the landlord. If the landlords have your dated signature on their copy, and additionally, accepts your rent money, when due, & has not presented you, with an eviction notice, unlawful detainer, or 3 day PROQ, it seems to me, that the landlord has a reasonable expectation that, you will be fulfilling the terms of the lease. If they have no reason, to want you out of the lease, but you do want out, simply stating,u201cthe landlord didnu2019t sign the lease copy I have, but he does have a copy, that I did, in fact, sign.u201dthat, is unlikely to get you any traction, on breaking the lease, or being refunded any monies.All of that having been said, IF, the terms of the lease are not being met, (habitability issues, quiet enjoyment issues, etc.) or if any of the clauses, that the landlord is obligated to uphold, are not being upheld, those are issues, that can sometimes, get you out of a lease. Showing there are issues, however, does NOT mean that it will get you out of the lease! Especially, if the issues are solved, addressed or repaired, to the satisfaction of lease terms, and within a reasonable timeframe.If you just donu2019t like the landlord, think heu2019s a jerk, or just had a better offer come along, only after you signed the lease, you could be stuck paying penalties to back out of the lease. Which is a great reason to ALWAYS thoroughly read, understand, & know what you are signing, before you sign anything!