I receive a "Status Code: 500" popup whenever I attempt to create a snapshot for a Windows VM from the Administration Portal UI. It doesn't matter if the VM is powered on or off. Nor the OS designation set in the UI (setting Linux or Other...). The modal usually states: "Operation Canceled" followed by "Error while executing action: A Request to the Server failed with the following Status Code: 500" or "Error while executing query: null". There are at least a dozen popups, and will continue to repeat every few seconds. The snapshot tab in the Admin Portal UI will then have issues displaying the Active VM and the newly created snapshot entry. If you try to examine both entries, the disk, network, and installed applications might appear blank. The web inspector will usually contain the following: Fri Dec 22 09:43:07 GMT-500 2023 org.ovirt.engine.ui.frontend.Frontend SEVERE: Failed to execute runQuery: com.google.gwt.user.client.rpc.StatusCodeException: 500 Internal Server Error The call failed on the server; see server log for details com.google.gwt.user.client.rpc.StatusCodeException: 500 Internal Server Error The call failed on the server; see server log for details The engine logs will have: File: server.log 2023-12-22 09:43:04,387-05 ERROR [io.undertow.servlet] (default task-726) Exception while dispatching incoming RPC call: com.google.gwt.user.client.rpc.SerializationException: Can't find the serialization policy file. This probably means that the user has an old version of the application loaded in the browser. To solve the issue the user needs to close the browser and open it again, so that the application is reloaded. ... snip ... Caused by: com.google.gwt.user.client.rpc.SerializationException: Type 'org.ovirt.engine.core.common.utils.SecretValue' was not included in the set of types which can be serialized by this SerializationPolicy or its Class object could not be loaded. For security purposes, this type will not be serialized.: instance = *** The same snapshot will appear fine in the VM Portal. I am able to see the network interfaces, and disks. No issues creating a snapshot of a Linux-based VM from either UI interfaces. I've tried in both Firefox (115.5 ESR) and Google Chrome (latest-ish). Any thoughts on where to look next? Version 4.5.6-0 (git12af746179.el8) on RHEL 8. Thank you, Jon