# Troubleshooting & FAQ

> Which file types you can upload, how a file gets attached to a task or policy, what the icons and counts mean, and why a document in use cannot be deleted.

Source: https://tidalcontrol.com/docs/evidence/troubleshooting-and-faq

Evidence questions are usually about what you can upload, how a file gets attached to a task or policy, and why a file cannot be deleted. Deletion is the one real constraint: only files that are not linked to anything can be removed.

## Frequently asked questions

### Which file types can I upload?

The upload function supports all file formats.

### How do I link documents to tasks or policies?

- **Link to tasks** - Go to the Tasks page and [Upload files there](/docs/tasks/handling-and-completing-tasks#uploading-files)
- **Link to Policies** - Go to the Policies page and [Upload files there](/docs/policies/creating-and-editing-policies#uploading-existing-documents)

### What do the icons and numbers mean for each document?

**Paperclip icon** - used as evidence
**Controls icon** - used as documentation in Controls
**Number** - How often the same document has been used. When uploading evidence and policies, previously used documents can be selected.

## Common problems

### Cannot select or delete document

To maintain audit trail integrity, only orphaned documents (not linked to tasks, policies, or vendor documentation) can be deleted.

### Still can't figure it out?

Send an email to support@tidalcontrol.com, and we'll get back to you as soon as possible.

> **info:**

**Gathering support info:** Note which browser you're using, exact error messages, and which steps you've already tried. This significantly speeds up the solution.