What causes a Unity TextMeshPro font atlas too large for CJK glyphs?

The TMP font asset is built in Static mode covering the full CJK range, so the atlas bakes thousands of glyphs into a huge texture even though only a few are used.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix a Unity TextMeshPro Font Atlas Too Large for CJK Glyphs

Q: How do you fix a Unity TextMeshPro font atlas too large for CJK glyphs?

Rebuild the TMP font asset in Dynamic atlas mode so glyphs render into the atlas on demand at runtime, keeping the shipped asset small instead of pre-baking thousands of characters.

Quick answer: Rebuild the TMP font asset in Dynamic atlas mode so glyphs render into the atlas on demand at runtime, keeping the shipped asset small instead of pre-baking thousands of characters.

A static atlas must contain every glyph you might display, and CJK ranges have thousands. That makes a multi-megabyte texture even when most glyphs are never shown. Dynamic mode adds glyphs to the atlas only as text uses them.

How to fix it

1. Switch the atlas to Dynamic

In the Font Asset Creator or the font asset's Generation Settings, set Atlas Population Mode to Dynamic so glyphs are rasterized on first use rather than all baked up front.

2. Pre-seed common glyphs

Add the characters you know you will show frequently to the asset's character table so they are present immediately, while rarer glyphs fill in dynamically.

3. Size the atlas sensibly

Set a reasonable initial atlas size with multi-atlas support enabled so the dynamic atlas grows in additional pages instead of forcing one oversized texture.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unity error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

Reproduce it once with full context and the fix writes itself. The hunt is the expensive part.