"Automatic Maintenance" is a potential time at which scheduled tasks can be run. There's some default ones, but any piece of software that adds scheduled tasks can add one to be run "at maintenance time".
Unfortunately Task Scheduler does not seem to display these tasks. But when maintenance is running, you can see what it is doing by opening Task Scheduler and choosing "display all running tasks" or running via schtasks | find "Running" at a command prompt.
You can see what it's going to do via schtasks | find "Queued".
I haven't fully verified this but it seems you can get the full list at any time by running schtasks /query /xml > tasks.xml and then searching the generated tasks.xml for any task with the element UseUnifiedSchedulingEngine and MaintenanceSettings.
Based on my install, here's the list in Windows 10. Note that not all of these necessarily run every Maintenance pass, and I couldn't find documentation for all of them.
- SmartScreenSpecific: updates application signatures for SmartScreen.
- ProgramDataUpdater: sends program telemetry data for Microsoft Customer Experience. Equivalent to
compattelrunner -maintenance.
- StartupAppTask: scans startup apps and warns the user if there are too many.
rundll32 Startupscan.dll,SusRuntask
- CleanupTemporaryState: clears temporary files in AppX (Metro/UWE) app packages.
rundll32 Windows.Storage.ApplicationData.dll,CleanupTemporaryState.
- DsSvcCleanup: runs
dstokenclean. Nobody seems to be sure what this does.
- Pre-Staged App Cleanup: part of the AppX cleanup process.
rundll32 AppxDeploymentClient.dll,AppxPreStageCleanupRunTask.
- ProactiveScan: Does a
chkdsk scan.
- BthSQM: something to do with Bluetooth SQM.
- KernelCeipTask: sends kernel telemetry data to Microsoft Customer Experience.
- UsbCeip: sends device driver telemetry data to Microsoft Customer Experience.
- ScheduledDefrag: runs the Windows Defragmenter:
defrag -c -h -o -$. This is often the task that takes the longest. Oddly, the -h switch makes it run at normal instead of low priority, which is odd for automatic maintenance.
- Diagnosis\Scheduled: runs Windows Diagnostics.
- SilentCleanup: runs Disk Cleanup:
cleanmgr /autoclean /d %systemdrive%.
- DiskDiagnosticDataCalculator: runs disk diagnostics.
rundll32 dfdts.dll,DfdGetDefaultPolicyAndSMART.
- DiskFootprint\Diagnostics: runs
disksnapshot -z. Nobody seems to be quite sure what this does, but it may be to do with Volume Shadow Copy.
- DiskFootprint\StorageSense: presumably this updates the Storage Sense statistics on the amount of space used by different file categories.
- ErrorDetailsUpdate. No clear information about this, but it's likely to do with collecting updates to system errors previously reported.
- Siuf\DmClient. SIUF is System Initiated User Feedback, so this is likely to do with the poll messages that can appear in Windows 10.
- File History Maintenance Mode. Runs a File History backup.
- IME\SQM Data Sender: This is presumably something to do with telemetry of unusual input methods (IME).
- TempSignedLicenseExchange. Probably something to do with temporary Windows licenses.
- WinSAT. Runs Windows System Assessment Tool, presumably for more telemetry.
- RunFullMemoryDiagnostic: what it sounds like; a RAM diagnostic.
- LPRemove: runs
lpremove which removes unnecessarily or unusable language packs.
- Plug And Play Cleanup: clears the state information for any Plug and Play devices which haven't been used for 30 days.
- AnalyseSystem: runs Power Efficiency Diagnostics.
- VerifyWinRE: checks the Windows Recovery Environment is intact.
- RegIdleBackup: makes a backup of the registry.
- MRTHB: runs MRT /EHB /Q. This is the Malicious Software Removal tool, so this is likely a security scan.
- StartComponentCleanup: cleans up the WinSxS directory that holds optional Windows component images.
- SettingSync\BackgroundUploadTask: uploads settings if you're using cloud sync.
- SettingSync\BackupTask.
- AccountCleanup: cleans up ancient user profiles on network shared machines.
- FamilySafetyUpload: upload logs from the parental control component.
- IndexerAutomaticMaintenance: update search indexes.
- SkyDrive\Idle Sync Maintenance Task, SkyDrive\Routine Maintenance Task: syncs SkyDrive documents.
- HybridDriveCachePrepopulate, HybridDriveCacheRebalance: Not fully documented, but likely tries to ensure that the SSD part of any hybrid drives attached has useful stuff in it.
- ResPriStaticDBSync.
- WsSwapAssessmentTask. This is presumably something to do with virtual memory.
- SystemRestore.
srtasks ExecuteScheduledSPPCCreation. Makes a Restore Point.
- SynchronizeTime.
sc start w32time task_started. Syncs the system clock.
- SynchronizeTimeZone.
tzsync. Connected to the above.
- Maintenance Install.
usoclient StartInstall. Installs any Windows Updates that have been downloaded but not installed yet.
- Work Folders Maintenance Work. Relates to the Work Folders file sharing server system.
