It's hard to tell which part is to blame for Canon digital camera not reading its sd card. This page tells 6 fixes that you may try to fix possible errors and determine which part of your camera or sd card is damaged to get to the root of the problem.
These solutions are for all Canon camera types with their memory card, not limited to these following types
Turn off the camera, pull out the sd card and check whether the sd card has been locked. When the lock switch is upside, it is not locked; otherwise it's locked from being read/write if the lock switch is downside.
Solution: Push the lock switch to upside to get it unlocked.
SD card is locked when the lock switch is down
No sd card lock to check? Use a card reader that has lock switch to turned it to off the lock.
When your camera Canon does not detect the memory card sd/sdxc/sdhc, the very first step is to get it power off. Pull out the sd card from your Canon, and insert it to pc for backup if it still could be recognized in the PC.
Copy all files on sd card, and then paste them to somewhere else on your hard drive volume as backup. We recommend you create a special folder for your sd card on your volume at first, and then you may copy and paste the files to get them all included in one folder.
Note: If your Canon camera has wifi, you may upload your data to somewhere as backup if you can still read it on sd card. (The bad, usually when sd card is not detected in Canon camera, neither can the data be read in normal ways.)
SD card not reading/accessible? => Restore data from sd card with special tool.
Canon SD Card Recovery (100% Safe)
When sd card is not accessible, some special professional tool such as iCare Data Recovery Pro can help retrieve data from sd card.
The above link involved a downloading for tools that include a first 1gb free recovery. It needs a subscription fee for more data recovery. This developer also shares some ways to get the code free.
An sd card reformatting may often resolve the read problem on Canon digital camera. Here are the steps to get it formatted.
Insert your sd card to computer with a card reader, and then open your computer THIS PC, the memory card will show as a volume here. Right click the sd card, and then format it.
If the right click format does not work, or when it reported unable to format, you may go to disk management and right click sd card to get it formatted.
Check sd card reader pin to see any bent on the pin since mostly it's one or more pins that were bent and the camera will not read the sd card
Video - why is camera not reading sd card
Possible Causes when Canon Is Not Reading SD Card
1. The memory card is not properly inserted into the camera (loose or other reasons), so that the camera cannot read it.
2. The metal contact of the memory card is oxidized. After taking it out and cleaning, reinstall it for test to see whether it can be read normally.
3. The memory card is in protected mode or locked.
4. Memory card sd is infected with virus.
5. There is a logic fault in the memory card, which can be solved by formatting under normal circumstances.
6. The memory card is damaged/read.
Canon camera common troubleshooting:
PartA, the flash does not glow
1, Not set the flash. Press the flash pop-up lever to set the flash.
2, The flash is charging. Wait until the orange light stops flashing
3, The photo object is bright. Use auxiliary flash mode.
4, The flash is working abnormally when the indicator lights up on the control panel when the flash has been set. It shall be repaired.
PartB, the camera does not function
1, The power is not turned on, press the power button to turn on the power.
2, The battery polarity is installed wrong. Reinstall the battery correctly.
3, Battery is exhausted. Renew the battery.
4, The battery is temporarily invalid. When using, please keep the battery warm; in between photos, do not use the battery temporarily.
5, The card cover is opened. Close the card cover.