Content Not Found" Error When Opening a Flow in Workflow Studio<!-- /*NS Branding Styles*/ --> .ns-kb-css-body-editor-container { p { font-size: 12pt; font-family: Lato; color: var(--now-color--text-primary, #000000); } span { font-size: 12pt; font-family: Lato; color: var(--now-color--text-primary, #000000); } h2 { font-size: 24pt; font-family: Lato; color: var(--now-color--text-primary, black); } h3 { font-size: 18pt; font-family: Lato; color: var(--now-color--text-primary, black); } h4 { font-size: 14pt; font-family: Lato; color: var(--now-color--text-primary, black); } a { font-size: 12pt; font-family: Lato; color: var(--now-color--link-primary, #00718F); } a:hover { font-size: 12pt; color: var(--now-color--link-primary, #024F69); } a:target { font-size: 12pt; color: var(--now-color--link-primary, #032D42); } a:visited { font-size: 12pt; color: var(--now-color--link-primary, #00718f); } ul { font-size: 12pt; font-family: Lato; } li { font-size: 12pt; font-family: Lato; } img { display: ; max-width: ; width: ; height: ; } } Symptom When opening an existing flow in Workflow Studio, the canvas displays a "Content Not Found" error and the flow does not render. The flow record exists, is active, has a populated snapshot, and the user has admin access. The issue occurs in both standard and incognito browser sessions. The following errors are present in the browser console (F12 → Console): Tried to get shared data for taxonomyTypes but no storage key found — loggerProvider.js:93Uncaught (in promise) TypeError: Cannot read properties of undefined (reading "toUpperCase") at createRequest (designer-bundle.min.js?v=27.0.13:398173)Invalid attribute value set for key: updatePayloadInvalid attribute value set for key: propertyValue Cause This is a known platform defect (PRB1815309) in the Developer App Shell component shipped with Yokohama Patch 12 HF1 (designer-bundle v27.0.13). When Workflow Studio initializes, it attempts to load shared taxonomy metadata (taxonomyTypes) into a storage key used by the designer bundle. On affected builds, this storage key fails to initialize correctly. When Workflow Studio subsequently attempts to build a request to render the flow canvas, it encounters an undefined value and crashes at the toUpperCase() call inside createRequest, surfacing as "Content Not Found" in the UI. The downstream Invalid attribute value errors are a cascade from the same initialization failure. This issue can affect natively created flows and is not caused by update set imports, browser state, scope misconfiguration, or user permissions. Resolution The fix is included in the Developer App Shell Bundle, released in Q1 2025. Instances running a build that includes or supersedes the Q1 2025 Developer App Shell Bundle are not affected by this defect. Still seeing this on a post-Q1 2025 build? If your instance is on a build released after Q1 2025 and you are encountering this error — particularly for a flow that has existed since before the fix was in place — that flow is the most likely cause, as it may have been affected before the fix was applied. Please open a support ticket referencing PRB1815309. We would be happy to investigate, though this issue does not appear to be reproducible on current builds. To apply the fix, contact Now Support referencing PRB1815309 to confirm the earliest available patch or hotfix for your specific release line. Workaround There is no guaranteed workaround on the affected build. The following steps may reduce recurrence but do not fully prevent it: Do not refresh the browser while inside Workflow Studio. Navigate away and return to the flow instead. Browser refresh is a known trigger for the taxonomyTypes initialization failure.Use incognito/private browsing when opening flows — this eliminates browser extension interference, though it does not resolve the underlying defect.If a flow becomes unrecoverable, raise a case with Now Support — backend recovery of the flow record may be possible. Prevention Stay current with patches. This defect is fixed in a later Yokohama bundle and will not affect upgraded instances.Export flows regularly via update set as a backup, particularly after significant changes, to avoid loss in the event of recurrence on older builds.If Now Support confirms a hotfix backport is available for your release line, apply it at the earliest opportunity. Additional Notes Issue is isolated to individual flows — other flows on the same instance may be unaffected.Instance health, DB latency, node status, and scope are not contributing factors.The affected component is the Developer App Shell (Workflow Studio front-end bundle), not the flow engine or execution layer.Natively created flows are affected — this is not limited to imported or cloned flows. Fix Status: This issue is resolved as of Q1 2025. If you are on a build released after Q1 2025 and are still seeing this error, please open a support ticket — we would be happy to investigate, as the issue does not appear to be reproducible at this time on current builds.