I got the following error after the following command:
pod install
[!] Unable to find a specification for
React-Coredepended upon byrn-fetch-blobYou have either:
- out-of-date source repos which you can update with
pod repo updateor withpod install --repo-update.- mistyped the name or version.
- not added the source repo that hosts the Podspec to your Podfile.
Note: as of CocoaPods 1.0,
pod repo updatedoes not happen onpod installby default.
Versions:
"react-native": "0.59.5",
"rn-fetch-blob": "^0.10.16",
Podfile:
...
pod 'rn-fetch-blob', :path => '../node_modules/rn-fetch-blob'
...
What Am I doing wrong? Is it an issue related to the version of the library?
Thanks
rn-fetch-blob 0.10.16 is only compatible with react native 0.60 and higher, I would recommend trying 0.10.15 with your project until you are able to upgrade
@fgagneten I am facing the same problem. Did you find any solution?
change your package.json from "rn-fetch-blob": "^0.10.15" to "rn-fetch-blob": "0.10.15", clean node_modules and npm install again
I just hit this today. Given that 0.10.16 is a breaking change, not a patch, shouldn't it have been published with a 1.X or at least 0.11.X version number so everyone doesn't auto-upgrade to it?
I apologize for the bad versioning scheme, yes this should have been at least a 0.11.x. Because this is a pre 1.0 library we haven't been following semantic versioning very well. I'll look into revising how we handle version numbers going forward though to reduce this problem.
For now I have updated the readme with a version compatibility warning
In rn-fetch-blob.podspec file锛寀pdate here
s.dependency 'React-Core'
change '-' to '/'
In rn-fetch-blob.podspec file锛寀pdate here
s.dependency 'React-Core'
change '-' to '/'
Worked for me.
@byk04712 and @bhagwandas, the opposite of this change is exactly what was put in 0.10.16, so you could just stay on 0.10.15.
I use expo sdk 34 (rn 0.59) and on package.json "rn-fetch-blob": "joltup/rn-fetch-blob#0.10.15" worked for me ;)
Anyone have a fix for this? On react-native 0.60.5 with rn-fetch-blob 0.10.16 but I can't install the pod.Unable to find a specification for React-Core depended upon by rn-fetch-blob. Any ideas?
@rardoz, it worked fine here. Maybe you forgot to clean something? You might try running pod deintegrate with xcode closed and pod install again.
1) change your package.json from "rn-fetch-blob": "^0.10.15" to "rn-fetch-blob": "0.10.15",
2) clean node_modules and npm install again
Works!
i actually had both this and the legacy unmaintained react-native-fetch-blob in my package.json.. remove that fixed it.. thanks yall
Still existing problem, can be fixed like this

In rn-fetch-blob.podspec file锛寀pdate here
s.dependency 'React-Core'
change '-' to '/'
This work for me
try remove the whole Pods directory, then pod install && pod update rn-fetch-blob
In rn-fetch-blob.podspec file锛寀pdate here
s.dependency 'React-Core'
change '-' to '/'
This work for me <3
In rn-fetch-blob.podspec file锛寀pdate here
s.dependency 'React-Core'
change '-' to '/'
I have a issue when upgrade expo version 32 to 33 (Ejecting to ExpoKit):
[!] Unable to find a specification for `React-Core` depended upon by `UMReactNativeAdapter`
And this solution was resolved my problem :)
Many Thanks!
if you are using RN version >60 then you should install this stable one.
"rn-fetch-blob": "0.12.0",
In rn-fetch-blob.podspec file锛寀pdate here
s.dependency 'React-Core'
change '-' to '/'
Works for me!!! Thanks a lot :)
after updating RN from 0.59 to 0.63 , I too got the same error.
I guess the issue is rnfechblob package is not maintained to work with new RN versions.
I uninstalled rnfrchblob package using
npm uninstall rn-fetch-blob
then installed again by
npm install --save rn-fetch-blob
cd ios
pod install
now issue is resolved for me.
https://github.com/joltup/rn-fetch-blob
this is where new rnfetchblob is maintained
This will do the trick for react native version ^0.62
s.dependency 'React'
if you're upgrading to react-native >= 0.62 make sure to have
require_relative '../node_modules/react-native/scripts/react_native_pods'
...
target <your app> do
...
use_react_native!(:path => config["reactNativePath"])
...
end
I missed this step in my upgrade and got the same error, adding in use_react_native! cleaned it up
Most helpful comment
change your package.json from
"rn-fetch-blob": "^0.10.15"to"rn-fetch-blob": "0.10.15", clean node_modules and npm install again