PI Settings Editor

A safe editor for PixInsight's core-NNN-pxi.settings file - user guide

Close PixInsight before editing. PixInsight keeps its settings in memory and overwrites the file with them when it runs or exits, which would undo anything changed here. PI Settings Editor detects a running PixInsight and switches to view-only until it is closed.

Getting started

On launch, the editor looks for core-NNN-pxi.settings in PixInsight's usual settings folder and opens the first one found. NNN is the PixInsight instance that wrote it - 001 is the ordinary case, 002 a second instance that was running at the same time. The File box at the top switches between every file found, or Browse... opens any other one.

The tabs, left to right:

Preferences - the common settings, grouped into pages with proper controls (checkboxes, dropdowns, spin boxes, paths, colors) and PixInsight's own descriptions. A changed row is highlighted; the arrow on its right reverts it.
Search (Ctrl+F) - finds a setting anywhere by name, folder path, description or value. Results are editable in place, just like on their own page.
Cleanup - data that can safely be removed (old process history, leftover module data, and similar), with its size, in two tiers - see Deleting entries. Tick what to remove, Queue for deletion, review, save.
Unused modules - settings left behind by modules that are no longer installed. Each one expands to show its entries and values; a whole module's data can be queued for deletion at once.
Health check - looks for settings that are probably wrong: a folder or file that does not exist on this computer, a number outside its documented range, an option value the editor does not recognize, more worker threads than the computer has processors, a registered module whose file is missing, a duplicated key, or a setting that allows unsigned content. Nothing is changed by the check itself; each finding shows the setting as an editable row.
Compare - the open file against another one (a second PixInsight instance, a backup, or any file you pick). Lists what differs, and copies chosen values across as ordinary pending edits.
All settings (advanced) - the complete tree, including every module's own data. Right-click an entry (or press Delete) for Delete this entry where that is allowed, or to see why it is not.

Saving, backups and deleting entries

Edits and deletions are queued, not applied immediately: a changed row is highlighted, a queued deletion is shown struck through, and Edit > Revert all changes undoes everything queued so far. Choosing File > Save opens Review changes first - every pending edit (before and after) and deletion (with the values it removes), with Revert selected to drop any one of them before committing.

Every save also, automatically:

refuses if PixInsight is running, or if the file changed on disk since it was loaded;
makes a timestamped backup, <file>.bak-YYYYMMDD-HHMMSS, first;
writes, then reads the result back and checks it matches what was intended.

File > Manage backups lists every backup of the open file and can keep only the newest few (a number you choose) or delete them all; removed backups go to the Recycle Bin/Trash. File > Restore backup brings any one of them back.

Only entries known to be safe are offered for deletion, in two tiers:

Tier	Meaning
Safe	Removing it cannot affect how PixInsight runs - e.g. a process's remembered window position, or a module's cached scratch data.
Warn	Usually fine to remove, but PI Settings Editor asks first, because it is less certain nothing depends on it.

Everything else has no delete option at all: core application settings, the module registry, and anything that could stop PixInsight starting or a module loading.

Warning. Not every entry in All settings (advanced) or the Health check is meant to be edited. PI Settings Editor flags values that are out of range or unrecognized, and a backup is only a Restore away - but if you don't know what a setting does, it's better to leave it alone.

Toolbar and appearance

The toolbar (View > Toolbar shows or hides it) repeats the everyday actions: Open, Reload, Save, Revert all, Find module, Backups, Restore, a Light/Dark switch (Ctrl+Shift+D) and About. The tabs are not repeated on it.

Edit > Theme switches between Light, Dark, or following the operating system. View > Larger text / Smaller text / Default text (Ctrl++ / Ctrl+- / Ctrl+0) resize everything but the toolbar. Both choices are remembered between runs.

Two shortcuts worth knowing

File > Find module data (Ctrl+M) - type a module's name and either search where module names usually appear (fast), or search everywhere the way Search does. Results land on the Search page, editable.
File > Unused module data - the same idea, but for every module that has leftover settings and is no longer in PixInsight's module list at all.

If something looks wrong

Message	What it means
"No PixInsight settings file found..."	None of PixInsight's usual settings folders (listed in the status bar) had one. Use Browse... to open a settings file from elsewhere.
"PixInsight is running - view only"	Editing is disabled until PixInsight is closed, to protect against it overwriting your changes on exit. Reopen the file (or press Reload) once it is closed.
"Not accepted - ..."	A typed value did not match what that setting expects (e.g. text where a number belongs); the row keeps its previous value.
A Health check finding	Explained in place, under the setting it refers to; nothing is changed until you edit that row yourself.