how to recover or repair corrupt or deleted image or video files

Image files that won't display

this may be because your software or operating system cannot display that format (eg. newer RAW files, HEIF files)
- check your software for an update
if the software does display some but not all, then it may be because the files have been corrupted - see below

if deleted in Windows, go to Recycle Bin on your Desktop and if it is there just Right-click and restore it
if it is not in the Recycle Bin or it was deleted in the camera, do NOT take further photos or save new files to that drive or memory card until you have tried to recover it
- deleting a file “permanently” just removes the index for that file from the system's File Allocation Table (FAT), tha actual file is still physically there (as long as it doesn't get over-written by a new file save) but not easily accessible
BEFORE you do anything, perhaps read my blog on how Windows CHKDSK can cause further problems, and how I solved them - see [SOLVD] Windows 10 Update corrupts 4Gb file then CHKDSK deletes it!

if it was a Sandisk SD card then your purchase usually includes option to download the SanDisk Recovery Software
I ended up purchasing EaseUS Data Recovery Wizard Pro version and this worked well for me - see my blog above
the above work well for:
- accidentally formatted memory card (as long as no new photos taken on it and as long as it was a “quick” format)
- accidentally deleted memory card (as long as no new photos taken on it)
- deleted photos from a session where no new photos in that session have been taken

a “QUICK” format (this includes formats done by the camera if the card has been previously formatted) just creates a new blank file allocation table (“FAT”) and directory table - the actual files are STILL there until they get over-written by new files, just not accessible by usual methods
a “FULL or NORMAL” format takes a long time, as in addition it checks for bad sectors and scrubs the old file structures replacing them with zeroes - the old files will NOT be able to be recovered by the above software
- magnetic memory disks such as conventional hard disk drives may still leave a trace of the old files and with super specialised software these may be able to be accessed.
- flash type memory such as SSD drives do not leave these traces and so the erased files will NOT be accessible without a lot of difficulty
- if you want to be 100% sure the data is deleted and unable to be accessible, use a disk-wiping program (eg. EaseUS BitWiper and KillDisk) which use algorithms to replace the data with dummy data and often in addition, rebuilds the Master Boot Record (MBR)

check the video player is able to play the video codec of your video files
- download the free VideoLan VLC media player - it generally runs most video codecs and is excellent

go to their website: https://main.grauonline.de/?page_id=5 and download the file
unzip the download
run gs.exe
press Choose Movie to select your corrupted file
press Choose reference movie to select a file that is NOT corrupted from the same camera
press Scan
you should hopefully have a recovered NEW video file in the subfolder called repaired
- if there was no audio, you may need to go into options and select ‘Enable AAC detection‘ (for AAC audio) or ‘Enable PCM audio‘ (for PCM audio) and try again
- however it seems there are no guarantees you will get a nice playback or have an audio track
if you are using the demo version this recovered video file will only be the 1st half of the file
- either pay for the app, or,
- double the size of the corrupted file before running it:
  - open command line editor (eg. type cmd in the Windows Search bar)
  - navigate to the folder of your corrupted file (eg. use DOS commands cd etc)
  - type copy /b bad.mp4 + bad.mp4 bad_double.mp4
  - where bad.mp4 is the name of your corrupted file and double.mp4 will be the name of your double sized file