Galaxy S7
Downloaded today’s update and click install but nothing happens. Warning in status bar shows “Install Error”
Same thing happened with the update previous, so I haven’t been installing any system updates.
Why does this happen?
There was a similar error for another device (Sony Xperia Z5 Compact - suzuran). The cause in that case was that an error in the /e/ build mean that the device could not reboot to recovery to install the update. It also meant that factory reset (which also requires a reboot to recovery) did not work either.
Does factory reset work for you? If not, the cause is likely to be the same.
The fix was made for suzuran in device specific code: it was a single line of code needed to be added in this gitlab commit. It may be that a similar fix is needed in the code for your device
Is there a way to do this without losing all my data?
Thank you
So you missed 2 updates now? You might tell us exactly your build now. You can get this easily from Settings > About phone > Android version > Long press on /e/ version will copy to clipboard.
There is a warning that you need a suitable Recovery, which Recovery do you have? The phone must be very well charged before you start.
At what stage had the process got to when it failed?
If that question is in response to my asking whether factory reset works, then you would first need to backup your data partition using TWRP
If factory reset does work then it will wipe all your apps and data. S it’s probably not a good idea to try 
A better way to find out whether your problem is the same as the suzuran bug is to capture a log file. There is a good description in this post on the XDA FOrums
https://forum.xda-developers.com/t/guide-providing-a-good-logcat.3814517/post-77033951
After steps 1 & 2, go for option B) SPECIFIC ISSUE and either upload the logfile here, or upload it to a site like pastebin.com, and post a link here
Correct.
Long press doesn’t so anything, however.
Android Version: 8.1.0
Build Version: e_he rooted user debug 8.1.0 OPM7.181205.0016701fddf70 dev-keys,dev-release
I used TWRP to image the device.
After downloading the update, I click Install. I get the Apply Update dialogue popup. I click OK. I get taken right back to where I clicked Install and bow a triangle warning appears in the status bar at the top. It shows Updater /e/OS 0.17 - Oct 23, 2021 Install error. If I click on it, the Apply Update dialogue pops up again for me to OK. And then the process repeats.
Thank you.
I do not recognise that build number, but trying to get the log as described above would be a good move.