Noticed the error in Joplin 1.2.2 beta Portable.
Doing a Reload or Force Reload doesn't have any effect.
Tried again using Joplin 1.3.18.2520 Portable and got the same error.
My OS is Windows 10 1903 build 18362.1139.
Here are the logs I see in the console:
internal/fs/utils.js:220 Uncaught Error: ENOENT: no such file or directory, open '\?\C:\Users\myself\AppData\Local\Temp\1hsBnkzcEmlbT16gbpOzoPBzzvr\resources\app.asar.unpacked\node_modules\node-notifier\package.json'
at Object.openSync (fs.js:440)
at Object.func (electron/js2c/asar.js:140)
at Object.func [as openSync] (electron/js2c/asar.js:140)
at Object.readFileSync (fs.js:342)
at Object.fs.readFileSync (electron/js2c/asar.js:542)
at Object.fs.readFileSync (electron/js2c/asar.js:542)
at Object.internalBinding.internalModuleReadJSON (electron/js2c/asar.js:633)
at readPackage (internal/modules/cjs/loader.js:231)
at readPackageMain (internal/modules/cjs/loader.js:274)
at tryPackage (internal/modules/cjs/loader.js:284)
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/fence.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/sanitize_html.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/checkbox.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/mermaid.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/markdownItAnchor.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/markdownItTocDoneRight.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/theme.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/light.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/type.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/dark.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/dracula.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/solarizedLight.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/solarizedDark.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/nord.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/aritimDark.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/oledDark.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/filterParser.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/queryBuilder.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/types.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/LockHandler.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/MigrationHandler.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/1.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/2.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/JoplinServerApi.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/SettingUtils.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/KeychainService.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/KeychainServiceDriver.node.js.map
DevTools failed to parse SourceMap: file:///C:/Users/myself/AppData/Local/Temp/1hsBnkzcEmlbT16gbpOzoPBzzvr/resources/app.asar/KeychainServiceDriverBase.js.map