> Source: Onevium official documentation
> Article: Preview, edit, and save local files
> Original URL: https://onevium.com/docs/file-editing
> Language: English
> Updated: 2026-09-28
> Applies to: 1.2.2+

---

# Preview, edit, and save local files

Open files from chat links or the project list, edit Markdown, text, and CSV, and distinguish Office previews, unsaved drafts, and disk changes.

## Identify the file you are viewing

Onevium opens local files from links in chat and from the project file list. Check the path at the top: editing a project file changes the original on disk, while an uploaded attachment may be a copy.

Use a practice project's `notes.md` containing a couple of ordinary notes. Choose a file that another task is not already editing.

## Open the target file

- Click **Browse all files** at the top of the conversation and select `notes.md`.
- You can also click a local file link in an assistant reply. References containing line numbers can locate particular content.
- In an open file, use the segmented path at the top to navigate directories or choose a neighboring file.

Check the path and content before editing. If access is missing, a file moved, or a temporary file expired, follow the panel's guidance to select the correct file again. A matching filename alone is not enough.

## Edit Markdown and save it

1. Open `notes.md`. Eligible Markdown files support editing in the preview surface; **Source** lets you inspect and edit the underlying text.
2. Append “Next: review the payment callback tests.” **Unsaved changes** at the top means the edit is still a draft.
3. Click **Save**, or use `⌘S` on macOS / `Ctrl+S` on Windows or Linux while the file editor is focused.
4. Wait for **Saved**, then reopen the file to verify. If saving fails, read the error; text visible in the editor is not proof that it reached disk.

Saving a file does not commit it to Git. Use **View changes**, or follow [Files, terminal, and Review](https://onevium.com/docs/files-terminal-review), to inspect the scope of the change.

## What each format supports

| File                                            | How to use it                                                                                             |
| ----------------------------------------------- | --------------------------------------------------------------------------------------------------------- |
| Markdown, plain text, and editable source files | Edit and explicitly save; Markdown can show formatted content or source                                   |
| CSV / TSV                                       | Preview as a grid; to change data, edit the delimited text in Source, save, then check columns in Preview |
| Excel workbooks                                 | Read-only worksheet preview; CSV text editing does not imply `.xlsx` editing                              |
| PDF, Word, PowerPoint                           | Read the preview; use the appropriate external application to edit the original document                  |
| Images, audio, and other media                  | View, zoom, or play as supported; previewing does not modify the file                                     |
| Oversized, truncated, or unsupported files      | The panel may offer only preview or an external-open option; follow its actual state                      |

For a CSV exercise, change one value in the source while preserving separators and quotes. Return to the grid and check that columns still align. A grid preview is not an Excel editor.

## When another task changes the file

An assistant, terminal command, or external editor can change the same file. The panel may then report **File changed on disk** or a conflict.

- Without unsaved edits, reload to see the current disk content.
- With a draft, preserve the text you need before deciding how to merge. Do not repeatedly save over another change while a conflict is reported.
- **Reload from disk** can discard the unsaved draft; read its confirmation first.

For concurrent tasks, use different files or separate working directories. Two split conversations pointing at the same directory still share its files.

## Verify the saved result

For a Git project, run this in the target project's terminal:

```bash
git diff -- notes.md
```

Confirm that only the intended line changed. For a non-Git project, reopen the file or check it in an external editor. A successful edit does not mean the entire project passes its tests.

## Troubleshooting

| What you see                                      | What to do                                                                                                      |
| ------------------------------------------------- | --------------------------------------------------------------------------------------------------------------- |
| No Save button                                    | Check that the format is editable and that you changed content; read-only previews do not offer editing actions |
| CSV looks like source code                        | Switch to Preview for a grid; use Source to edit its data                                                       |
| The original project does not change after saving | Check whether this is an attachment copy or a same-named file in another directory                              |
| A file conflict is reported                       | Preserve your draft, inspect disk changes, then merge or reload                                                 |
| An Office document cannot be edited               | Use an external application; the panel offers a read-only preview                                               |

## Next steps

Use [Review and the terminal](https://onevium.com/docs/files-terminal-review) to inspect file changes, or [Input tools](https://onevium.com/docs/tools-menu) for attachments, file references, and queued messages.