ERROR CODE 218 - error unboxing chat message (transient): Not found: User in method chat.1.local.getThreadNonblock

I'd been using the keybase chat app on my MacBook Pro (High Sierra) until a week or two ago when I reinstalled the operating system. I then started using it on an Ubuntu desktop. When I reinstalled the app on my fresh instance of High Sierra, and verified the new device via paper key, it logged in fine, remembered which users I had active chats with, but will not show me messages or let me send messages. The error message I get is pasted below.

I've tried installing different builds, I've tried re-verifying the device, etc, and cannot get around this error. Any ideas?

``
Error: ERROR CODE 218 - error unboxing chat message (transient): Not found: User 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 at u (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:441796) at _rpcClient.invoke.t (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:245338) at file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1758890 at e.t.Deferrals.e._call (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649609) at file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649760 at s (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649389) at e.t.Deferrals.e._fulfill (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1649719) at s (file:///Applications/Keybase.app/Contents/Resources/app/desktop/dist/index.bundle.js:1:1648923)
``

Start by reproducing the failure after verifying a fresh High Sierra device, focusing on chat.1.local.getThreadNonblock and the reported ERROR CODE 218. The report names only the packaged desktop bundle, not a source file; done means messages display and sending messages works without the transient unboxing error.

Written by the indexing model from the issue text.