There are a couple of scripts available for GP to deactivate all reports. Ian Grieve adds a twist to his with Deactivate All Reports (Except PM EFT Payment Register) In All Companies
Deactivate All Reports (Except PM EFT Payment Register) In All Companies | azurecurve
Reporting & BIPayables & ReceivablesMicrosoft & the GP Ecosystem
Archived post from 2014. Dynamics GP and the links it points to have changed since; check current documentation before relying on version-specific steps.