We need to update our Microsoft Exchange Server (2007) to SP3 in order to set up a hybrid environment to facilitate staged migration to O365, however we are unable to install either SP2 or SP3.
When running the SP2 setup - it passes the checks - but fails with the error 'Unable to remove product with code 24b2c164-de66-44fe-b468-a46d9d5e6b31. This update package could not be opened. Error code is 1635.
We have tried re-downloading the package - no luck.