# Cache Generation

> When generating a cache there was no dataset selected.

## Error: Cases_base: Failed to Load Data: Query-string Expression Not Valid: Expression Error: Expression Expected.

### Cause

When generating a cache there was no dataset selected.

### Solution

Make sure the client has selected a working dataset in popup menu when generating a cache. See illustration below.

![docs image](https://dev-assets.cms.uipath.com/assets/images/process-mining/process-mining-docs-image-58289-dfbb3ed9-9c428674.webp)

## AppOne Files Not Found in Git Tree When Generating Cache

### Cause

The `Application.mvp` of **AppOne** is expected to be in the root of the workspace of a release.

### Solution

Make sure that the `Application.mvp` is in the root of the workspace.

![docs image](https://dev-assets.cms.uipath.com/assets/images/process-mining/process-mining-docs-image-58340-0447b434-bee4b3db.webp)

## Error: Data Missing in Dataset: Cases_events_input

### Cause

The **BasicConnector** is released instead of **AppOne** and it was tried to generate a cache using that release.

### Solution

Make sure there is a release from **AppOne** active instead of a release of a connector.

## Error: Invariant Failed: "……" or Warning: Invariant Failed: "……"

### Cause

Within **AppOne** there are several invariants, some are errors, and some are warnings. These invariants are expected to be true. If an invariant is false this will be shown when generating the cache. With an error invariants the cache generation is aborted while the cache generation will continue with warning invariants. The name of the invariant that failed is displayed in the message.

### Solution

Look at what invariant failed and what the name of it is. The invariants all have descriptive names guiding you into what is wrong, for example, **Error: Event_end is empty**. This means that `event end` in your dataset is empty and therefore an error is thrown and the cache generation stops. **Warning: Case has no events** means that there are cases within your dataset that have no events. In this case, the cache generation will continue.

## Related Information

See [Cache Generation](https://docs.uipath.com/process-mining/standalone/2021.10/user-guide/process-mining-cache-generation#cache-generation).