Data transfer issues

[JoAlT]

So my father has used up storage on his phone with pictures of grand babies to the point where his Pixel 3 will no longer allow him to even use the camera to to lack of storage even after deleting unnecessary files taking up space of his phone. He doesn’t want to buy anything new or use something like the cloud. I have offered to transfer via usb all his pics to a 1Tb thumb drive that I bought. I already did this for my mom when she had the same problem. I have successfully transferred photos from all but two or three files. He organizes the pictures into labeled files in the gallery on his phone. Those labeled files transferred well and show up under “PICTURES” on his phone and the ones he hasn’t organized yet are still in “CAMERA/DCIM” I have tried changing usb settings and two different times I have “successfully” transferred 490+ Images along with a few videos in the “camera” file to the thumb drive. I follow proper procedure for ejecting mass storage device but when I go to check the thumb drive the next day...all those 490+ files are not there on the thumb drive where they should be. The file where they were copied is empty! How is this possible? What do I do?!

 

[plodr]

How is the 1TB drive formatted?
In this thread it mentions that Pixels only auto mount FAT32 drives.
https://forum.xda-developers.com/t/pixel-3a-copy-files-to-a-usb-flash-drive.4126285/

Also did you connect the drive by an OTG cable?

Are his photos automatically backed up to the cloud, using Google photos? If so, this might be an easier way of obtaining the pictures on another device
https://www.technipages.com/google-photos-usb-drive

Note: I don't own a pixel and I do not have my photos backed up to the cloud. I attach my phone to one of my computers and copy my photos there then I can make a 2nd copy on a USB stick or micro sd card to archive.

 

[JoAlT]

I don’t know how it is formatted. It is a standard USB drive with 1 Tb of storage space. I plug it into my PC and also plug in the phone via usb cable to PC. I open file for thumb drive on PC and file for Pixel files side by side with two different windows of File Explorer. Then I just drag and drop/copy and paste the files. They go through the full process...the amount of available storage decreases on the USB after I add the files showing that files have been transferred...I safely eject and the put it back in aaaannnddd “file is empty” is what I see. But the space those files took is still showing as having been used on the little space availability bar when you look at it in the MY PC folder. I have changed settings to show hidden files. I have run a scan for external storage devices via Kaspersky to look for malware with nothing showing. The space on the usb is used but nothing is showing for the camera section...but it shows up just fine for other sections I had transferred.

 

[plodr]

On the 1TB drive, right click and select properties. What does it say?