https://devzone.nordicsemi.com/f/nordic-q-a/17213/nrf5x_mdk_8_9_0_keil-errorHi, I use PCA10040 v1.1, Keil MDK 5.21a, SDK 12.1 with S132 v3. I was using SDK 12 previously. The SDK 12 projects worked well. Now I migrating to the new SDK. So I removed and reinstalled the pack installer. By the way, my desktop&#39;s environmenten-USTelligent Community 13Fri, 21 Oct 2016 08:35:04 GMThttps://devzone.nordicsemi.com/thread/66127?ContentTypeID=1Fri, 21 Oct 2016 08:35:04 GMT137ad170-7792-4731-bb38-c0d22fbe4515:94e6bdf3-0029-4daa-98bf-af71afa23a94J&#248;rgen Holmefjord<p>Happy to help! Please accept the answer and upvote if this solved your problem.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/66126?ContentTypeID=1Fri, 21 Oct 2016 08:16:40 GMT137ad170-7792-4731-bb38-c0d22fbe4515:15ec6b71-4f41-41ad-8f09-e26e7dd702f5MANGO<p>LoL, thanks for you help. I used IAR for a long time. So I made some mistakes while using KEIL.</p> <p>Thanks.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/66125?ContentTypeID=1Fri, 21 Oct 2016 08:04:05 GMT137ad170-7792-4731-bb38-c0d22fbe4515:233e0277-d48b-4d95-9141-30d0ecacd17eJ&#248;rgen Holmefjord<p>You should not have to install <code>nRF5x_MDK_8_9_0_Keil4.msi</code> if you use Keil v5, this is only for Keil version 4. You should install the MDK through the package installer. Try clicking the green arrows in the left corner to update all packs. Afterwards, see if you can find NordicSemiconductor::nRF_DeviceFamilyPack v8.9.0 in the list on the right and click install.</p><div style="clear:both;"></div>