Samsung Galaxy S25 Ultra and Galaxy S24 Ultra owners are reporting severe battery drain, overheating and slower charging after installing the company’s latest July security update.

Complaints have appeared across Samsung Community forums and Reddit, with affected users claiming the problems began immediately after downloading the patch.

One Galaxy S25 Ultra owner said their battery fell from around 85% at midnight to just 5% by midday, despite recording only about two hours of screen-on time.

The user claimed the device was losing between 5% and 7% of its charge every hour while idle. Galaxy S24 Ultra owners have reported similar problems, saying handsets that previously lasted an entire day now require charging much earlier.

Other users said their devices were becoming unusually hot during light use, while some reported significantly slower charging speeds.

The problem does not appear to affect every Galaxy S24 Ultra or S25 Ultra owner, suggesting the fault may be linked to a particular app or software configuration rather than the update alone.

Some users believe WhatsApp’s encrypted backup feature may be responsible. Reports suggest the update can leave WhatsApp’s backup process stuck, causing the app to repeatedly run in the background and consume additional power.

Several affected owners said disabling encrypted backups, completing a fresh WhatsApp backup and then re-enabling encryption returned battery consumption to normal. However, the workaround has not been confirmed by Samsung and may not resolve every case.

Samsung has yet to publicly acknowledge the complaints or confirm whether a software fix is being developed.

Affected users can check battery usage under the device’s settings to identify apps consuming unusual amounts of power, but may ultimately need to wait for another firmware update.