Re: my sd card was wiped after the lollipop update on my s5
Welcome to Android Central! That's puzzling on a number of levels. First, did the update start on its own, without asking you? That shouldn't happen--unless you had already declined it multiple times over the past few weeks or so. On many devices, after a certain number of refusals, it may force you to accept the update.
SD cards aren't supposed to be affected during a system update--but that being said, we have seen posts here from unfortunate people who've had it happen to them. It always seems to be with Samsung devices, so it might be some specific glitch in the Samsung update process.
Did you have your contacts saved to your Google account, or only to the local Phone/Device account? I always recommend saving or associating contacts with your Google account, because they get synced immediately to your Google Contacts in the cloud, and are safe. It helps you recover easily from disasters like this. Saving to the local Phone account only is a problem, because that account doesn't sync anywhere automatically--you have to use a 3rd party program (like Kies) to manually backup data regularly.
Contacts wouldn't be saved on the SD card, so it's not clear why you lost them. Some phones allow you to save contacts on the SIM card, but that's usually very limited--a SIM can only hold around 250 contacts or so. Were all of your photos on the SD card? The card may have become corrupted during the update, as mentioned above. Unmount it (in
Settings>Storage), remove it, and insert it into your computer, and run chkdsk to look for bad sectors:
http://forums.androidcentral.com/am...guide-using-chkdsk-fix-corrupted-sd-card.html