On an older, slower PC with rotational disks, if there are many files contained within a vault, and particularly when CryFS is used, "opening" the vault can take several seconds. After the password is entered and "OK" clicked, there is no indication of anything happening, the password entry box remains on screen. It would be better if there was some form of visual feedback to indicate the vault is being opened. In the form of a popup window perhaps, or simply by changing the cursor to "Busy/Wait".
Can you re-test the latest version as there is a new password entry dialogue which tries to show that something is happening?
Sorry, no longer using Vault. Hopefully an active user of it will provide feedback.