A new bug has been discovered in the latest software update to the HTC One M9 that is causing extremely long charging times.

Owners of the HTC One M9 who have updated their software for the device have reported charging times that take as long as 13 hours, according to Phone Arena.

The latest software update for the HTC One M9 is version 1.40.401.8 and updating to it might not be a good idea, according to reports from two Italian users of the device.

After they updated to the latest software, Samuel Brancaccio and Enrico Martini said that fully charging the 2,840 mAh battery for the HTC One M9 took as long as 13 hours. The normal charge time for this smartphone is 106 minutes, or less than two hours.

A screenshot of the HTC One M9's lock screen has the text of "Charging - 13 hours until complete" displayed near the icons at the bottom of the screen.

The Twitter account for HTC UK is apparently aware of the issue. "This is an issue we are aware of since the last update on the M9, if you uninstall Google Photos application..." it tweeted to Martini. 

This is all that the tweet said and it is unknown if uninstalling Google Photos is the problem that is causing the abnormally slow charging or if it is the solution.

Another user tweeted the HTC UK account and said that deleting the Google Photos app and clearing the cache did not solve the issue. HTC recommended restarting the phone by holding the power and volume up keys for 15 to 30 seconds before charging, according to Tech Radar.

One known fix for this bug is turning off or restarting the One M9 when it is charging. This is not a convenient solution, but it will have to do until HTC officially addresses and fixes the bug.