Copying login keychains between Macs fails on Secure Enclave Macs with Tahoe

TEXT START: I recently encountered an issue with the login keychain on macOS.

The Dissection

This is a narrow forensic report documenting a shift from portable, password-unlocked files to hardware-bound authorization. The test shows that copying login.keychain-db and supplying the correct password does not reproduce access in a macOS VM. The database moves; the authority to decrypt its contents does not.

The article’s deeper significance is that it treats a sovereignty failure as a migration problem. The user still possesses the file and password, but the platform’s Secure Enclave controls whether possession has any practical meaning.

The Core Fallacy

The technical inference is plausible, but the evidence is narrower than the headline. The demonstrated test is Apple Silicon Mac to a VM without a Secure Enclave. It does not establish that every manual transfer between two Secure Enclave-equipped Macs fails.

Relative to DT mechanics, the larger error is treating this as a file-compatibility defect. It is an authority migration: control has moved from a portable artifact and human-held password into platform-controlled hardware identity. The file is no longer the credential. It is merely a stranded container.

Hidden Assumptions

• The Secure Enclave binding is the decisive cause, without fully excluding other Tahoe, account, metadata, or file-state causes.
• An identical username and password imply an equivalent keychain identity.
• Behavior observed with a VM generalizes to Mac-to-Mac migration.
• Migration Assistant operates like raw database copying, though it may use a different reconstruction process.
• The cited logs prove the conclusion, even though the supplied text does not actually reproduce their contents.
• “No longer works” applies broadly, despite the test covering one source Mac and one VM destination.

Social Function

Partial truth and transition management. The article accurately documents a real loss of portability and gives administrators a warning. It also normalizes platform custody by presenting the loss of user control as an implementation detail to work around, rather than naming it as a structural transfer of sovereignty.

This is not copium. It is a useful autopsy whose field of vision stops at the operating-system boundary.

The Verdict

Technically useful but evidentially limited. It establishes that password knowledge is no longer sufficient when key material is bound to a source Secure Enclave; it does not prove universal failure across all Secure Enclave Macs or explain how supported migration tools behave.

Under the Discontinuity lens, this is a small but clean example of the same underlying pattern: portable human control is replaced by infrastructure-mediated permission. The user owns the database. The platform owns the conditions under which the database is usable.