# ERROR: Can't start iodevice (keyboard) and no alt tag specified Extended information **URL:** \ **Category:** Support\ **Created:** [May 18, 2023, 2:09pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891 "2023-05-18T14:09:04Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![jdhwang](https://avatars.discourse-cdn.com/v4/letter/j/85e7bf/32.png) [@jdhwang](https://mworks.discourse.group/u/jdhwang)\ **Post date:** [May 18, 2023, 2:09pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/1 "2023-05-18T14:09:04Z")
I have below issue even though I added MWserver to input monitoring ```auto 00:03:43: Display bounds set to (-17.658 left, 17.658 right, 11.0324 top, -11.0324 bottom) 00:03:43: ERROR: Unable to open HID manager (status = -536870203) 00:03:43: ERROR: Can't start iodevice (keyboard) and no alt tag specified Extended information: parser_context: mw_finalize ``` ![image](https://canada1.discourse-cdn.com/flex031/uploads/mworks/original/1X/ed1e82984775abb3e9c0f509cff46be6161deefc.png) For your information, I am using 0.13dev on Ventura 13.3.1(a) ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [May 18, 2023, 3:24pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/2 "2023-05-18T15:24:00Z")
Hi, Did you restart MWServer after allowing it to monitor keyboard input? That’s probably a necessary step. Cheers, Chris Stawarz ---
**Author:** ![jdhwang](https://avatars.discourse-cdn.com/v4/letter/j/85e7bf/32.png) [@jdhwang](https://mworks.discourse.group/u/jdhwang)\ **Post date:** [May 18, 2023, 5:32pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/3 "2023-05-18T17:32:49Z")
Hi Chris, Yes, I did and I even restarted my computer several times. Thanks, Jaedong ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [May 19, 2023, 12:47pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/4 "2023-05-19T12:47:03Z")
Hi Jaedong, That’s strange. Maybe try removing MWServer from the “Input Monitoring” permission list entirely: Click on its entry in the list, then click the “-” button at the bottom. After that, launch MWServer and load an experiment that uses the keyboard. You should be notified that MWServer needs permission. Enable it, then close and reopen MWServer once more. Hopefully, at that point, the experiment will load successfully. Cheers, Chris ---
**Author:** ![jdhwang](https://avatars.discourse-cdn.com/v4/letter/j/85e7bf/32.png) [@jdhwang](https://mworks.discourse.group/u/jdhwang)\ **Post date:** [May 19, 2023, 12:49pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/5 "2023-05-19T12:49:37Z")
Hi Chris, I think I did that yesterday but will try right now again. I will let you know in 10 minutes. Thanks, Jaedong ---
**Author:** ![jdhwang](https://avatars.discourse-cdn.com/v4/letter/j/85e7bf/32.png) [@jdhwang](https://mworks.discourse.group/u/jdhwang)\ **Post date:** [May 19, 2023, 12:55pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/6 "2023-05-19T12:55:31Z")
Hi Chris, It does not work. Here is the video clip I what I did, [MWServer does not work. - YouTube](https://youtu.be/268XiSwj6cQ). For your information, this code worked from my colleague’s macbook. Thanks, Jaedong ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [May 19, 2023, 1:49pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/7 "2023-05-19T13:49:07Z")
Hi Jaedong, Thank you for sending the video. I see that the “Unable to open HID manager” message is reporting two different error codes. The first, which is shown before you’ve given input monitoring permission to MWServer, is -536870174. The symbolic name for this error is `kIOReturnNotPermitted`, which makes sense, since MWServer needs permission to open the HID manager. The second, which is shown after you’ve given permission, is -536870203. The name for this error is `kIOReturnExclusiveAccess`, and the source code for it includes the comment “exclusive access and device already open”. What this second error suggests is that another process (not MWServer) has obtained exclusive access to the keyboard and is thereby preventing MWServer from using it. And in fact, based on [this discussion](https://stackoverflow.com/questions/65470681/iokit-call-fails-with-kioreturnexclusiveaccess-when-another-app-is-running), it looks like Karabiner (the only other app on your system that appears to have input monitoring permission) does precisely that. Given this, I think you either need to disable Karabiner entirely or find some way to prevent it from claiming exclusive access to the keyboard. (Maybe there’s a preference for that?) Cheers, Chris ---
**Author:** ![jdhwang](https://avatars.discourse-cdn.com/v4/letter/j/85e7bf/32.png) [@jdhwang](https://mworks.discourse.group/u/jdhwang)\ **Post date:** [May 19, 2023, 2:05pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/8 "2023-05-19T14:05:35Z")
Hi Chris, I actually thought the same thing yesterday and it did not work. I also tried today and here is the video [MWServer does not work v2 - YouTube](https://youtu.be/7kq4b3aXf2E) Thanks, Jaedong ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [May 19, 2023, 2:22pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/9 "2023-05-19T14:22:19Z")
There’s probably a Karabiner helper process still running in the background. I suggest either uninstalling Karabiner entirely, or working on a Mac that doesn’t have it installed. In any case, I am 99.9% certain that this is not an MWorks issue. Cheers, Chris ---
**Author:** ![cstawarz](https://yyz1.discourse-cdn.com/flex031/user_avatar/mworks.discourse.group/cstawarz/32/3_2.png) [@cstawarz](https://mworks.discourse.group/u/cstawarz)\ **Post date:** [June 6, 2023, 1:04pm UTC](https://mworks.discourse.group/t/error-cant-start-iodevice-keyboard-and-no-alt-tag-specified-extended-information/891/10 "2023-06-06T13:04:08Z")