What it means
Navigation is pointing to a file that the package does not currently treat as part of normal reading order.
EPUB error guide
TOC target not in spine (RSC_011)
Use this when a TOC or navigation reference points to a file that is not in the OPF spine. Check the reading order before you change nav.xhtml, toc.ncx, or content.opf.
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Match these report titles
- toc target not in spine
- RSC_011 referenced resource is not a spine item
- TOC target is not a spine item
- Referenced resource is not in the OPF spine
Start here
Check the navigation target against the reading order.
In an EPUB package, RSC_011 means navigation points to a file that the OPF spine does not currently treat as part of the reading order.
Can it be fixed automatically?
The scan can locate the navigation entry, manifest item, and current spine state, but it does not automatically add a file to the reading order or retarget the TOC.
What to check next
Find the nav.xhtml or toc.ncx entry that points to the non-spine resource.
What not to assume
It should stop when the fix would choose chapter order, appendix placement, front matter behavior, or alternate navigation intent on behalf of the author.
1. Example report output
What the RSC_011 report should show.
The report should prove whether the target file should be in the reading order or whether the TOC points to the wrong document.
EPUBCheck message
ERROR(RSC-011): Referenced resource is not a spine item.
Navigation target
nav.xhtml points to Text/appendix.xhtml#toc-appendix.
Spine status
appendix.xhtml exists in the manifest but is not listed in the spine.
Do this next
Decide manually whether appendix.xhtml belongs in the reading order or the TOC should point elsewhere.
Do not do this
Do not add random files to the spine or retarget the TOC just to clear the validator.
The report identifies the two possible edits, but adding a spine item or retargeting navigation changes book flow and remains manual.
2. Next step
Choose what to inspect before a manual RSC_011 edit.
The next step depends on whether the navigation points to the right file and the spine is missing it, or whether the navigation points to the wrong file entirely.
Scan first
You only know the target is not a spine item.
Use the scan to see which nav or NCX entry points outside the spine and which manifest item sits behind it.
Manual decision
Confirm whether the file belongs in the reading order.
Use the source project or EPUB editor to add the itemref only after confirming its intended position, or retarget the TOC after confirming the real destination.
Manual review
The chapter flow is unclear.
Stop when adding the file to the spine or retargeting the TOC would change chapter order, front matter, appendix behavior, or reader navigation intent.
3. Concrete path example
A typical RSC_011 navigation mismatch.
The file exists, but the reading order does not currently include it.
EPUBCheck: ERROR(RSC-011): Referenced resource is not a spine item. Report: TOC target: OEBPS/Text/appendix.xhtml#toc-appendix Manifest item: appendix.xhtml exists Spine itemref: not present Fix decision: manual — confirm whether to add a spine itemref or retarget the TOC
If the TOC should point to another existing chapter instead, do not add the wrong file to the spine automatically.
Quick decision
Decide whether the file belongs in the spine or the TOC points to the wrong place.
RSC_011 sits at the boundary between navigation wiring and book structure, so guessing can change how readers move through the book.
Scan first
You need the target file and spine status together.
Read the nav or NCX target, the manifest item, and the spine itemrefs before editing either navigation or reading order.
Manual edit
Confirm the intended destination and reading-order position.
The report can narrow the choice, but an author or EPUB editor must decide whether to change the spine or the navigation target.
Stop
The structure choice affects the book flow.
Do not decide appendix placement, front matter order, or alternative navigation behavior automatically.
Common situations
Common RSC_011 cases.
Start with whether the TOC points to the correct content file.
A real chapter file is missing from the spine.
The TOC points to a chapter XHTML file that exists, but the spine omitted it.
Confirm its exact reading-order position in the source project or EPUB editor before adding the itemref.
The TOC points to back matter or appendix outside the intended flow.
The file exists, but whether it should be in the spine depends on the book structure.
Choose manually before editing the spine.
nav.xhtml or toc.ncx points to the wrong file after export.
A navigation entry survived from an older chapter split or rename.
Confirm the intended destination manually before retargeting navigation.
The file exists but is intentionally not part of the reading order.
Some files should not become normal reading-order items even if a bad navigation link points to them.
Remove or rewrite the navigation reference instead of forcing the file into the spine.
The RSC_011 spine-target error text
RSC_011: Referenced resource is not a spine item.
Where RSC_011 usually appears
EPUBCheck, Kindle Previewer, or KDP finds a TOC or navigation target that resolves to a manifest item not included in the OPF spine reading order.
What it means
RSC_011 usually means TOC wiring and reading order disagree.
This often happens after chapter splits, appendix changes, front matter edits, stale nav.xhtml or toc.ncx links, or manual OPF cleanup that removed a spine itemref.
Before you edit
Compare the TOC target, manifest item, and spine itemrefs.
Do not add a file to the spine or retarget the TOC by guess. First confirm whether the destination should actually be part of the book's reading order.
- 1Find the nav.xhtml or toc.ncx entry that points to the non-spine resource.
- 2Resolve that target to the manifest item and file path it uses.
- 3Check whether that manifest item appears in the OPF spine itemrefs.
- 4Decide whether the file clearly belongs in the reading order or whether the navigation target itself is wrong.
- 5Stop when the change would choose book flow, appendix placement, or front matter structure by guess.
Why KDP checks it
Why validators reject navigation targets outside the spine.
EPUB 3.3 package rules
The OPF file is the EPUB's map: metadata, file list, reading order, and navigation wiring. KDP and EPUBCheck use it to decide whether the book package is coherent.
EPUBCheck
EPUBCheck checks EPUB 2 and EPUB 3 files against the official rules and reports package, markup, link, and file-reference problems.
Repair example
Why RSC_011 remains a manual repair.
Before / after example
Before: a TOC entry points to a file outside the spine. Next: confirm whether the file belongs in the reading order and at which position, or whether navigation should point to another existing spine item; then edit manually and validate again.
Ready to retry?
Scan navigation and reading order together.
A good report should show the nav.xhtml or NCX target, the manifest item it resolves to, and whether that item belongs in the spine.
Upload EPUB to scanFAQ
Questions authors ask about RSC_011.
What does RSC_011 mean?
It means navigation points to a file that is not currently in the OPF spine reading order.
Can EPUB Fixer repair RSC_011 automatically?
No. The scan can show the navigation target, manifest item, and spine state, but choosing whether and where to add content to the reading order or which TOC destination is intended requires manual review.
Should I always add the file to the spine?
No. Sometimes the navigation points to the wrong file. Adding a file to the spine by guess can change the book's reading order.
Is RSC_011 related to missing Kindle TOC problems?
Often, yes. A TOC can exist but still fail when its entries point to files outside the intended reading order.