Log files

The desktop app keeps a plain-text log of what it does: each launch, sign-in links arriving from your browser, and update checks and downloads. When something doesn't behave (a sign-in link that leaves you signed out, an update that never arrives), that file usually says why, and it is the first thing support will ask for. Sign-in links are logged without the sign-in tokens they carry.

Where the logs are

Platform	Log file
macOS	~/Library/Logs/led-fyi/main.log
Windows	%APPDATA%\led-fyi\logs\main.log
Linux	~/.config/led-fyi/logs/main.log

The folder is called led-fyi on every platform: the app's short system name, the same one macOS shows in Hide led-fyi (see The desktop app).

To open the folder:

• macOS: in Finder choose Go → Go to Folder… (⇧⌘G), paste ~/Library/Logs/led-fyi, and press Return.
• Windows: press Win + R, paste %APPDATA%\led-fyi\logs, and press Enter.
• Linux: open ~/.config/led-fyi/logs in your file manager, or run xdg-open ~/.config/led-fyi/logs. If you set XDG_CONFIG_HOME, the folder is $XDG_CONFIG_HOME/led-fyi/logs instead.

Once the log grows past about 1 MB, the older part is moved to main.old.log in the same folder and a fresh main.log starts. If both files are there, send both.

Sending a log to support

1. Reproduce the problem once, so it is in the log.
2. Attach main.log (and main.old.log, if there is one) to your email to support, and say roughly what time the problem happened.

Every launch writes a line naming the version and the data folder that copy of the app is using:

[2026-09-20 18:04:11.530] [info] LED.FYI 2.0.4 · name=led-fyi userData=/Users/you/Library/Application Support/led-fyi

That line is how support tells which version wrote each part of the file; see the next section.

Older log files you might find

Don't debug against the @led-fyi/desktop log

Test builds of the new desktop app numbered below 2.0.0 named themselves @led-fyi/desktop, so they logged to a different place:

Platform	Test builds below 2.0.0 logged to
macOS	~/Library/Logs/@led-fyi/desktop/main.log
Windows	%APPDATA%\@led-fyi\desktop\logs\main.log
Linux	~/.config/@led-fyi/desktop/logs/main.log

From 2.0.0 on, the app logs to the led-fyi folders in the first table. If one of those test builds is still installed on the machine, it can keep adding recent, real-looking update activity to the old file, so a fresh timestamp there does not mean it's the log of the app you're running. Always read the led-fyi log.

The 1.x app also logs to the led-fyi folder, into the same main.log. On a machine that has been upgraded from 1.x you may find its older lines above the 2.x ones; the startup line with the version number (above) shows where each launch of 2.x begins.