# How to identify when an air filter was changed on the iSeq 100

**This content is applicable for iSeq 100 systems.**

1. C:\ProgramData\Illumina\iSeq Control Software\\
2. Open the Maintenance.xml file with Notepad or an available text viewer software.
3. The air filter change date is found in line: 'MostRecentAirFilterReplacementDate'

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