Iâm getting a walkback while attempting to look at the prior versions of certain methods. It happens on some methods, but not all. I think the the issue may be related to having characters in the method body that are represented as multi-byte sequences in UTF-8. The error is 'Illegal leading byte for utf-8 encodingâ from ZnUTF8Encoder Here are the top few stack frames: ZnUTF8Encoder>>error: ZnUTF8Encoder>>errorIllegalLeadingByte ZnUTF8Encoder>>nextCodePointFromStream: ZnUTF8Encoder(ZnCharacterEncoder)>>nextFromStream: ZnCharacterReadStream>>nextElement ZnCharacterReadStream(ZnEncodedReadStream)>>peek SourceFile>>peek ChunkReadStream(DecoratorStream)>>peek ChunkReadStream>>skipSeparators ChunkReadStream>>basicNextChunk ChunkReadStream>>next SourceFileArray>>readOnlyDo: BlockClosure>>ensure: SourceFileArray>>readOnlyDo: SourceFileArray>>changeRecordsFrom:className:isMeta:do: SourceFileArray>>changeRecordsFrom:className:isMeta: VersionBrowser>>buildChangeList VersionBrowser>>buildBrowser VersionBrowser>>browseVersionsOf: Everything looks reasonable. The underlying ZnBufferedReadStream is at position 2, and the first few bytes are 159 166 34 39 46 or, in hex: 9F A6 22 27 2E That first byte, 9F or 10011111, is not valid as the first byte in a UTF-8 sequence (itâs a valid continuing byte) â which presumably is why ZnUTF8Encoder is complaining. So, why is the VersionBrowser starting to look at that particular place in the source file? VersionBrowser >> buildChangeList looks like this: buildChangeList rgMethod sourcePointer ifNil:[ ^ #() ]. ^ (SourceFiles changeRecordsFrom: rgMethod sourcePointer className: rgMethod instanceSideParentName isMeta: rgMethod isMetaSide) collectWithIndex: [ :c :i | | rg | rg := c asRingDefinition. rg annotationNamed: #versionIndex put: i ] and rgMethod sourcePointer is the value of the sourcePointer attribute in the attributes dictionary in rgMehod. What can be done to fix this? Andrew