# NFCReaderError.Code Reader session and tag error codes. ``` enum Code ``` ## Topics ### Session Errors [`NFCReaderSessionInvalidationErrorFirstNDEFTagRead`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorFirstNDEFTagRead) The first NDEF tag read by this session is invalid. [`NFCReaderSessionInvalidationErrorSessionTerminatedUnexpectedly`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorSessionTerminatedUnexpectedly) The reader session terminated unexpectedly. [`NFCReaderSessionInvalidationErrorSessionTimeout`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorSessionTimeout) The reader session timed out. [`NFCReaderSessionInvalidationErrorSystemIsBusy`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorSystemIsBusy) The reader session failed because the system is busy. [`NFCReaderSessionInvalidationErrorUserCanceled`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorUserCanceled) The user canceled the reader session. [`NFCReaderSessionInvalidationErrorFirstNDEFTagRead`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorFirstNDEFTagRead) The first NDEF tag read by this session is invalid. [`NFCReaderSessionInvalidationErrorSessionTerminatedUnexpectedly`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorSessionTerminatedUnexpectedly) The reader session terminated unexpectedly. [`NFCReaderSessionInvalidationErrorSessionTimeout`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorSessionTimeout) The reader session timed out. [`NFCReaderSessionInvalidationErrorSystemIsBusy`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorSystemIsBusy) The reader session failed because the system is busy. [`NFCReaderSessionInvalidationErrorUserCanceled`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerSessionInvalidationErrorUserCanceled) The user canceled the reader session. ### NDEF Tag Errors [`NFCNdefReaderSessionErrorTagNotWritable`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorTagNotWritable) The NDEF tag isn’t writable. [`NFCNdefReaderSessionErrorTagSizeTooSmall`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorTagSizeTooSmall) The NDEF tag memory size is too small to store the data. [`NFCNdefReaderSessionErrorTagUpdateFailure`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorTagUpdateFailure) The reader session failed to update the NDEF tag. [`NFCNdefReaderSessionErrorZeroLengthMessage`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorZeroLengthMessage) The NDEF tag doesn’t contain an NDEF message. [`NFCNdefReaderSessionErrorTagNotWritable`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorTagNotWritable) The NDEF tag isn’t writable. [`NFCNdefReaderSessionErrorTagSizeTooSmall`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorTagSizeTooSmall) The NDEF tag memory size is too small to store the data. [`NFCNdefReaderSessionErrorTagUpdateFailure`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorTagUpdateFailure) The reader session failed to update the NDEF tag. [`NFCNdefReaderSessionErrorZeroLengthMessage`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/ndefReaderSessionErrorZeroLengthMessage) The NDEF tag doesn’t contain an NDEF message. ### Transceive Errors [`NFCReaderTransceiveErrorRetryExceeded`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorRetryExceeded) Too many retries have occurred. [`NFCReaderTransceiveErrorTagConnectionLost`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorTagConnectionLost) The reader lost the connection to the tag. [`NFCReaderTransceiveErrorTagNotConnected`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorTagNotConnected) The tag isn’t in the connected state. [`NFCReaderTransceiveErrorTagResponseError`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorTagResponseError) The tag has responded with an error. [`NFCReaderTransceiveErrorSessionInvalidated`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorSessionInvalidated) The reader session is invalid. [`NFCReaderTransceiveErrorPacketTooLong`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorPacketTooLong) The packet length exceeds the limit supported by the tag. [`NFCReaderTransceiveErrorRetryExceeded`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorRetryExceeded) Too many retries have occurred. [`NFCReaderTransceiveErrorTagConnectionLost`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorTagConnectionLost) The reader lost the connection to the tag. [`NFCReaderTransceiveErrorTagNotConnected`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorTagNotConnected) The tag isn’t in the connected state. [`NFCReaderTransceiveErrorTagResponseError`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorTagResponseError) The tag has responded with an error. [`NFCReaderTransceiveErrorSessionInvalidated`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorSessionInvalidated) The reader session is invalid. [`NFCReaderTransceiveErrorPacketTooLong`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerTransceiveErrorPacketTooLong) The packet length exceeds the limit supported by the tag. ### Tag Command Configuration Error [`NFCTagCommandConfigurationErrorInvalidParameters`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/tagCommandConfigurationErrorInvalidParameters) The tag has been configured with invalid parameters. [`NFCTagCommandConfigurationErrorInvalidParameters`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/tagCommandConfigurationErrorInvalidParameters) The tag has been configured with invalid parameters. ### Other Errors [`NFCReaderErrorUnsupportedFeature`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorUnsupportedFeature) The reader session does not support this feature. [`NFCReaderErrorInvalidParameter`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorInvalidParameter) An input parameter is invalid. [`NFCReaderErrorInvalidParameterLength`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorInvalidParameterLength) The length of an input parameter is invalid. [`NFCReaderErrorParameterOutOfBound`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorParameterOutOfBound) A parameter value is outside of the acceptable boundary. [`NFCReaderErrorRadioDisabled`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorRadioDisabled) The NFC wireless radio on the device is disabled. [`NFCReaderErrorSecurityViolation`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorSecurityViolation) A security violation associated with the reader session has occurred. [`NFCReaderErrorUnsupportedFeature`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorUnsupportedFeature) The reader session does not support this feature. [`NFCReaderErrorInvalidParameter`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorInvalidParameter) An input parameter is invalid. [`NFCReaderErrorInvalidParameterLength`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorInvalidParameterLength) The length of an input parameter is invalid. [`NFCReaderErrorParameterOutOfBound`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorParameterOutOfBound) A parameter value is outside of the acceptable boundary. [`NFCReaderErrorRadioDisabled`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorRadioDisabled) The NFC wireless radio on the device is disabled. [`NFCReaderErrorSecurityViolation`](/documentation/CoreNFC/NFCReaderError-swift.struct/Code/readerErrorSecurityViolation) A security violation associated with the reader session has occurred. ## Relationships ### Conforms To [`RawRepresentable`](/documentation/Swift/RawRepresentable) [`Hashable`](/documentation/Swift/Hashable) [`Equatable`](/documentation/Swift/Equatable) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable) [`Sendable`](/documentation/Swift/Sendable) --- Copyright © 2026 Apple Inc. 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