> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hightouch.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Error handling

> Understand how Hightouch handles events that fail to write to your warehouse.

Sometimes Hightouch can't write an event to your warehouse. This can happen
for a variety of reasons; for example, the warehouse credentials may be
invalid, or your event schema may have evolved to have incompatible types.
When it happens, Hightouch retries the event and stores unresolved failures so you can replay them later.

## Viewing sync errors

Sync errors can be found under the sync run page.

The run summary page provides a quick summary of the types of errors that are
keeping your data from being synced.

![Error summary screenshot](https://mintcdn.com/hightouch-3c037897/L_vQfA0JQEpeGUUo/images/events/error-summary.png?fit=max\&auto=format\&n=L_vQfA0JQEpeGUUo\&q=85\&s=89ed342c6c25e38ce11f28931ac702d1)

For each error, you can see how many events it's affecting, as well as
individual examples of bad events.

![Sample error payload screenshot](https://mintcdn.com/hightouch-3c037897/L_vQfA0JQEpeGUUo/images/events/sample-error-payload.png?fit=max\&auto=format\&n=L_vQfA0JQEpeGUUo\&q=85\&s=7e14ebd98b36862eab9fa32037662790)

## Retrying data

Invalid data is automatically retried for at least 48 hours. If the data issue
has still not been resolved, the invalid events are stored so that they can be
replayed at a later date.

Replaying events is done via the "Archived Failures" screen.

![Archived failures screenshot](https://mintcdn.com/hightouch-3c037897/L_vQfA0JQEpeGUUo/images/events/archived-failures.png?fit=max\&auto=format\&n=L_vQfA0JQEpeGUUo\&q=85\&s=dfa3d6dbbeddd8b740d7604b37cb10a5)

### Fixing column types

To change an existing column type, you can create a temporary version of the
column with the new format.

For example, the following query may used on Snowflake to change the `price`
column on the `product_ordered` table from an `INT` to a `FLOAT`:

```
BEGIN;
ALTER TABLE product_ordered ADD COLUMN price_float FLOAT;
UPDATE product_ordered SET price_float=price;
ALTER TABLE product_ordered DROP COLUMN price;
ALTER TABLE product_ordered RENAME COLUMN price_float TO price;
COMMIT;
```