Engine Error: CValueExpressionState::DoValidateContent: Unable to parse and evaluate expression

In investigating the Engine logs, the error "CValueExpressionState::DoValidateContent: Unable to parse and evaluate expression" is found. The services are running as normal, and there may be no noticeable degrade in performance / functionality. What does this mean?

Environments:

• Qlik Sense Enterprise, all versions

This kind of error means that the engine tried to evaluate an expression in a document, and could not because the expression is not formed correctly.
This error is thrown regardless if the Engine Logging is set to Debug level or not.

There are several approaches one can attempt to find the errant expression:

Simplest: Talk to your developers/users

1. ​Talk to your developers or users. There is a high possibility they are already aware of the expression/issue.
2. Either fix the expression (if in production), or if this has no impact disregard the error. We discourage disabling logging entirely.

Detailed: Use the logs to find the source of the expression
       1. Locate one particular error in the logs, for example from the Trace > System_Engine logs:

58081    20180224T092809.066+0100    ERROR    YOURSERVERNAME    System.Engine.Engine    285    ea094a97-53d0-4106-90c8-3044cd1c0c90    
DOMAIN\QLIK-SERVICE-ACCOUNT    CValueExpressionState::DoValidateContent: Unable to parse and evaluate expression    
e31a65d9-b8ad-4725-a2b8-3c183339103e    DOMAIN USERNAME    20180224T092809.069+0100    7224    6204    
20180215T185245.000+0100    ea094a97-53d0-4106-90c8-3044cd1c0c90

       2. Look at session id (e31a65d9-b8ad-4725-a2b8-3c183339103e) in the Audit > AuditActivity_Engine logs around the time of the issue (20180224T092809). You should be able to narrow down the issue at this point to particular users, apps, or sheets by looking at all objects being opened at or prior to the timestamp for the session established.
       3. Approach the users you suspect are using this app. Ask them to use the app, while you monitor the engine logs. If you see the error reproduced while the app is using a particular sheet or object, then you should at this point be able to narrow down your search for the errant expression with the app's developer.

Lowest Effort: Hire Consulting Services

1. Reach out to Consulting Services or your Account Owner (at a cost), see How to Contact the Consulting Team?.