While we do not have support for making your Personal Capital Cash account a joint account just yet (it's coming soon!), we do allow for transferring funds from your linked joint accounts.
In order to transfer funds, make sure that your name on your Personal Capital Cash account matches your name on the joint account- if it does not match, we will not allow transfers from this account.
Additionally, if you have your own set of login credentials for accessing the joint account, make sure that you have the account linked to your Personal Capital dashboard using your login credentials. For example, if you have a joint account at your spouse's bank you may have used their login credentials in order to include the rest of their accounts at that bank in your dashboard. If that is the case you will need to re-add the joint account using your login credentials, then mark the original instance of the joint account as closed. For help with marking accounts as closed, please see our FAQ here: How to Mark an Account as Closed in Personal Capital
If your name matches exactly and you are using your login credentials for the account but still see errors with transferring funds, please contact Personal Capital Cash support at firstname.lastname@example.org