A platform update is available and will be applied automatically when Steam is restarted. The changes include:

STEAM CLIENT CHANGES / ADDITIONS:

Added Tools section to Steam UI Fixed Japanese, Thai, and Russian characters drawing incorrectly under Windows 98 Fixed DoD:S showing up in the Steam monitor as downloading Fixed HL2 preloading stuck at 89% for some users Fixed condition causing "non-zero size of m_uMallocedBlock" message