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When the execution of WuInstall is aborted for some reason before WuInstall can reset the registry value, it have has to be reset manually!
/use_wsus wsus_address
The /use_wsus option works similar to the /bypass_wsus option, but you can specify another WSUS, which is valid during the execution of WuInstall (or it allows you to switch from no WSUS at all to a certain WSUS).
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