It will usually finish if you just let it go, but.... per this thread and my own use of the procedure
Link
Also:
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When installing this roll-up to a new installation of Windows 7 SP1 and/or Windows Server 2008 R2 SP1:
Install the KB3102810 and KB3083710 updates, reboot
Then install the April 2015 servicing stack update (with no reboot) KB3020369
Then install the CR
o “Servicing Stack Update” KB3020369 must be installed first, or the roll-up will report “the update is not applicable”. Update KB3020369 is a relatively small update and can be applied with no reboot.
· This roll-up consumes approximately 2 GB of disk space after installation.
o During installation, this roll-up may use approximately 4 GB of disk space. About ½ of the 4 GB will be released during the restart after installation, as the temporary disk space used by the roll-up installer is released.
>>> Disable your network connection until the reboot after installing the rollup. Otherwise the WU client may try to contact WU and start the process of comparing what is in the OS now versus what is available.
>>> Instead of choosing the option "Automatically install" when presented with the option for Windows updates, users should choose "Ask Me Later" when installing the rollup.
>>> After reenabling their network connections, users should then change the Windows Update setting
"Living tomorrow is everyone's sorrow.
Modern man's daydreams have turned into nightmares.