Waiting for participants to rekey

Ever since one of my contacts reset their account, our pre-reset messages display a lock and a "Waiting for participants to rekey" message. Clicking the "Rekey" button does nothing or alternatively displays the following error. My username and my contact's username have been replaced with the placeholders {$MY_USERNAME} and {$CONTACT_USERNAME}:

Error: ERROR CODE 218 - error unboxing chat message (transient): This device does not yet have read access to directory /keybase/private/{$MY_USERNAME},{$CONTACT_USERNAME} (files before {$CONTACT_USERNAME} account reset 2018-01-23), log into Keybase from one of your other devices to grant access: could not find params for uid=6f43483e361c0e7edaa627d695595619 device key=01218bbff920baebccea332b992e51cc10d664e64d0aade04d73761fd83cc40f23330a github.com/keybase/kbfs/libkbfs.(*KeyManagerStandard).getTLFCryptKeyParams /Users/build/go/src/github.com/keybase/kbfs/libkbfs/key_manager.go:311 github.com/keybase/kbfs/libkbfs.(*KeyManagerStandard).getTLFCryptKey /Users/build/go/src/github.com/keybase/kbfs/libkbfs/key_manager.go:157 github.com/keybase/kbfs/libkbfs.(*KeyManagerStandard).getTLFCryptKeyUsingCurrentDevice /Users/build/go/src/github.com/keybase/kbfs/libkbfs/key_manager.go:81 github.com/keybase/kbfs/libkbfs.(*KeyManagerStandard).GetTLFCryptKeyOfAllGenerations /Users/build/go/src/github.com/keybase/kbfs/libkbfs/key_manager.go:65 github.com/keybase/kbfs/libkbfs.(*KBFSOpsStandard).GetTLFCryptKeys /Users/build/go/src/github.com/keybase/kbfs/libkbfs/kbfs_ops.go:587 github.com/keybase/kbfs/libkbfs.(*KeybaseServiceBase).GetTLFCryptKeys /Users/build/go/src/github.com/keybase/kbfs/libkbfs/keybase_service_base.go:1315 github.com/keybase/kbfs/vendor/github.com/keybase/client/go/protocol/keybase1.TlfKeysProtocol.func2 /Users/build/go/src/github.com/keybase/kbfs/vendor/github.com/keybase/client/go/protocol/keybase1/tlf_keys.go:206 github.com/keybase/kbfs/vendor/github.com/keybase/go-framed-msgpack-rpc/rpc.(*callRequest).Serve /Users/build/go/src/github.com/keybase/kbfs/vendor/github.com/keybase/go-framed-msgpack-rpc/rpc/request.go:76 github.com/keybase/kbfs/vendor/github.com/keybase/go-framed-msgpack-rpc/rpc.(*receiveHandler).handleReceiveDispatch.func1 /Users/build/go/src/github.com/keybase/kbfs/vendor/github.com/keybase/go-framed-msgpack-rpc/rpc/receiver.go:121 runtime.goexit /usr/local/Cellar/go/1.10.3/libexec/src/runtime/asm_amd64.s:2361 in method chat.1.local.getThreadNonblock at new r (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:441228) at file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:441757

Start by tracing the rekey failure through libkbfs/key_manager.go, especially getTLFCryptKeyParams at line 311, then follow the related KBFS key retrieval calls in the reported stack trace. Check how the desktop client's Rekey action reaches this path. Done means pre-reset messages no longer remain locked and the Rekey action completes without the reported error.