topic Re: Canon EOS 300D Information for BurnUnit (Whiz) in EOS DSLR & Mirrorless Cameras

Canon EOS 300D, error 99

Telegraphist — Sat, 14 Mar 2026 22:43:16 GMT

My camera is showing Error 99 and I have tried everything on the internet and AI but cannot sort it. Both my expensive lenses work perfectly well when I take a picture but once I have pressed the button the error 99 comes up, and to enable me to take another photograph, I have to switch it off and then turn it back on again. The CF card also records the photographs OK.

Therefore, should I reset it to factory settings?..

Re: Canon EOS 300D

deebatman316 — Sat, 14 Mar 2026 22:40:12 GMT

Hi @Telegraphist which lenses are you using and which one is causing the problem. Please provide the FULL and COMPLETE NAMES of ALL lenses. It sounds like you have a problem with that lens if every other lens works correctly. A complete name of a lens would be EF-S 18-55mm F/3.5-5.6 IS STM lens or EF 24-105mm F/4L IS II USM lens. Are you using any 3rd Party lenses or other items on your camera such as a flash or batteries. I have example lenses below to help you identify your lenses. Please be clear which lenses DO WORK and lenses which DO NOT WORK.

Re: Canon EOS 300D, error 99

Telegraphist — Sun, 15 Mar 2026 08:55:57 GMT

I shall come back to you soon with photographs of the 2 lenses I use. Though I have to say, I can take photographs with these lenses and they download to the 1GB CF card OK. However, once the photograph is taken the error 99 comes up on the screen.
But of course to be able to take another photograph I have to switch the camera off and then back on to take another photograph. Which is very frustrating.

Re: Canon EOS 300D, error 99

Telegraphist — Sun, 15 Mar 2026 11:12:15 GMT

Re: Canon EOS 300D, error 99

rs-eos — Sun, 15 Mar 2026 12:32:53 GMT

Error 99 is a general error and thus it could be due to different things.

If you haven't already, try cleaning the lens contacts (on both the lenses and camera). See: https://support.usa.canon.com/kb/s/article/ART177686

You could also try a factory reset, but try cleaning contacts first.

Re: Canon EOS 300D, error 99

ebiggs1 — Sun, 15 Mar 2026 14:25:32 GMT

"If you haven't already, try cleaning the lens contacts ..."

To the OP, you can try cleaning the contacts but I can almost 100% guarantee it won't help. The next "remedy" that will be offered but also will not help is a FW update. The easiest and most likely, hopefully, are the memory card or bad battery. Next a bad lens. The next not so easy is a shutter malfunction and after all your camera is getting on in years.

A full reset might help but certainly won't hurt. Speaking of hurting if you must clean the lens and camera contacts do it carefully as you can do unrepairable damage if done incorrectly. A qtip and a little denatured alcohol. Do not use a pencil eraser as some suggest. Try your lenses on somebody else's camera just to make sure they work properly. Buy a new Canon brand or at least a top quality battery. Buy a new top quality CF card. BTW, I can't remember but your camera may have a keep alive battery if it does make sure you replace it, too.

I am sorry to say but the likely problem is the shutter.

Re: Canon EOS 300D, error 99

Telegraphist — Sun, 15 Mar 2026 14:31:06 GMT

Thanks for your reply Ricky.

I have already done the cleaning process, and if you read the above the 2 lenses work and take photographs and download them to the 1GB CF card. But once the photograph has been taken the err 99 comes up on the LCD monitor. If I want to take another photograph I have to turn the camera off and then back on again to enable me to take another photograph. This is a pain in the backside and not the right way to use the Canon EOS 300D.
I did send a message to Deebatman316 along with pictures of my lenses, which he asked for, so will see what he has to say, before I look for my next move, in particular the factory reset, or whether I look at getting it repaired.

Re: Canon EOS 300D, error 99

deebatman316 — Sun, 15 Mar 2026 14:41:14 GMT

@Telegraphist Error 99 usually means shutter failure in older DSLRs such as yours. Your camera is no longer repairable by Canon any longer. It’s not worth repairing it. It’s best to look into a new EOS R Series Mirrorless camera now. As Canon has discontinued DSLRs and EF/ EF-S lenses. Support is ending for that platform and everything associated with it.

Re: Canon EOS 300D, error 99

Telegraphist — Sun, 15 Mar 2026 17:53:57 GMT

Actually, I bought a second hand Canon EOS 300D complete with its original lense. It cost me £36.00 and £2.60. I have inserted a 1GB CF card and it works perfectly with both the lenses I showed you.

As for the 300D which has the err 99, I have looked at the internet and I have found details that could cure the error, it does mean unscrewing the back cover. So I will have a go. If it doesn’t work it will go in the bin. But at least I am now back to taken pictures with a remarkable cheap second hand Canon EOS 300D.

Re: Canon EOS 300D, error 99

Telegraphist — Sun, 15 Mar 2026 17:55:16 GMT

By the way the £2.60 was for delivery to my house in Stafford United Kingdom

Re: Canon EOS 300D, error 99

Telegraphist — Sun, 15 Mar 2026 18:01:30 GMT

Actually, I bought a second hand Canon EOS 300D complete with its original lense. It cost me £36.00 and £2.60 for delivery to my house in Stafford United Kingdom. I have inserted a 1GB CF card and it works perfectly with both the lenses I showed deebatman316

Re: Canon EOS 300D, error 99

BurnUnit — Mon, 16 Mar 2026 05:14:33 GMT

The Digital Rebel/300D does have a seperate memory battery for date and time functions. If you can't remember when you last changed it then it's probably due. Something cheap and easy to try.

Also remove the CF card, get a lighted magnifier, and have a good look down into the card slot in the camera body. See if any of the fine contact pins are broken, bent or displaced. If so, you can safely assume the camera is irrepairable, at least as far as the cost and effort involved.

If the card contacts are OK, try using a different CF card and format it in the camera. Maybe try to avoid using a card larger than maybe 8GB or 16GB. The older cameras may have a problem recognizing the really large capacity newer cards.

Re: Canon EOS 300D, error 99

ebiggs1 — Mon, 16 Mar 2026 14:23:13 GMT

"I have found details that could cure the error, it does mean unscrewing the back cover."

Well all I can say is, good luck. This, whatever procedure you got from the ole inner web, is not likely to help or fix it or make it work. Have at it.

"See if any of the fine contact pins are broken, bent or displaced."

Also a very low, to none, of a chance of fixing it as this is not the problem if the camera addresses the CF card. Besides the camera will work even if there is no CF card installed at all.

"Error 99 usually means shutter failure in older DSLRs such as yours."

Already affirmed in my first reply. In reality, most of the suggestions offered are just a shot in the dark and usually have no impact. But some can be destructive.

Re: Canon EOS 300D, error 99

Telegraphist — Mon, 16 Mar 2026 15:10:56 GMT

By the way my friend the title of my name Telegraphist means I was one of those Radio Guys in the Royal Navy for 21 years and I am also an amateur radio guy callsign G0GUF so I ain’t no plank when it comes to electronics. I have done all the stuff you and others have suggested, and I afraid it appears you and perhaps others such as deebatman 316 only come up with ideas that are are already out there on AI and YouTube and some times your bottom line appears to me ‘buy a new camera zip fullstop’ Well I ain’t into that.

My personal opinion is that you should be saying, what part of the world do you live, so that we (Canon) might find somebody who sells their cameras and does repairs. Instead of saying the Canon EOS 300D is unrepairable, hence why I will give it a whirl and see what transpires.

Re: Canon EOS 300D, error 99

deebatman316 — Mon, 16 Mar 2026 15:39:30 GMT

@Telegraphist this forum is hosted by Canon USA. It is mainly focused on U.S. & Canadian based users. But people from other countries do comment and use these forums. When it comes to entry level cameras such as the Digital Rebel (NA model name)/ EOS KISS Digital (Japan)/ EOS X00D series. The cost to repair it greatly exceeds the value of a replacement of the same model. Also users in this forum don’t work for Canon. Unless the user’s name has a “Canon” badge attached to their username. Then they work for Canon USA. Canon will always suggest their service centers. Never a 3rd Party company to provide repairs. My grandfather did electronics repair from the mid 60s until his retirement in 2005. When he retired he already saw the electronics industry moving to non repairable items. VCRs, DVD/ CD Players & TVs. You can buy a new TV for cheaper than repairing your current one.

Re: Canon EOS 300D, error 99

Telegraphist — Mon, 16 Mar 2026 15:53:41 GMT

So what’s that got to do with what I said.

Yes I guess the world is changing to throw away items instead of repair, but as experience tells me, I like to have a go at repairing things if I can. And certainly your comment about you can buy a new TV for cheaper than repairing your current one, certainly does not apply to buying an amateur radio transceiver costing thousands of pounds, when most repairs by the owner such as me cost a few pounds.

Re: Canon EOS 300D, error 99

Stephen — Mon, 16 Mar 2026 16:03:59 GMT

Neither ebiggs1 or BurnUnit work for Canon. They are normal users like you. Since they don't know your life history, they're telling you that this camera is 23 years old (it's the first digital SLR we made), and if it's giving you a "generic" error 99 code, if you can't determine almost immediately why, usually the best bet is to recycle it.

Of course, if you choose to tinker with it, that's your prerogative. We (Canon USA) don't have parts for this camera any longer, and we cannot be held responsible for any damages if you attempt repairs yourself.

Re: Canon EOS 300D, error 99

LeeP — Mon, 16 Mar 2026 16:06:40 GMT

Well said!!

Re: Canon EOS 300D, error 99

LeeP — Mon, 16 Mar 2026 16:10:57 GMT

I like tinkering. I bought two "for parts only" old Pentaxes and was able to get one working very easily by grabbing a couple of parts from the other. I was 100% resolved that the attempt could fail, but why not try? Give the old camera a tinker and see what happens. Keep us posted. I for one am all ears.

Re: Canon EOS 300D, error 99

Telegraphist — Mon, 16 Mar 2026 16:17:13 GMT

So if they don’t work for Canon where do they get there information from, that it’s unrepairable and trying tell me how I can proceed by saying I should buy a newer one.
Therefore if I decide to attemp repairs it’s got nothing to do with Canon and should it not work then at least I have tried and it will then go in the bin.