Discord server
Guide

Map too large to host or download

Big maps fail in two ways: the game refuses them, or players sit in the lobby while the download crawls. Both start with measuring what takes the space.

What you see

  • The editor or Battle.net refuses to host the map.
  • Joiners' download counters freeze in the lobby and the start button stays disabled.

Why it happens

Each era has a size limit: 4 MB before 1.24b, 8 MB from 1.24b and 128 MB from 1.27b. For Reforged the community cites about 500 MB. We found no published number from Blizzard, so treat it as unconfirmed.

Imported HD models and textures, voice-over and music take most of the space, and large maps download slowly in lobbies.

How to fix it

  1. List imports by size and remove the ones nothing uses.
  2. Convert textures to compressed BLP or DDS at the resolution you need, and use OGG for audio (supported since 3.0).
  3. Ship variants. One large project publishes Full, SD and Lite builds of the same map.
  4. Ask players to put a large map into Documents\Warcraft III\Maps\Download under the same file name before they join.

How WC3 Map Doctor detects it

Rules that look for this
  • Severe
    The archive is larger than the limit of the target build (8 MB on 1.26, 128 MB on 1.27b to 1.31).
    PERF-F01
  • Warnings
    The archive is larger than 256 MB, which Battle.net players download slowly or not at all.
    PERF-F01-bnet
  • Info
    An imported texture is larger than 1024 pixels on a side.
    PERF-A02
  • Info
    An imported WAV file is larger than 1 MB.
    PERF-A06
  • Info
    An imported file is not referenced by any model, object, script string or UI file.
    PERF-A07

Operations that fix it on a copy

  • optimize.imports Remove unused imports

Sources

Written in our own words from our lab notes; these are the pages behind them.