我发现的解决办法是编辑预定义的URL链接，只需在更新站点URL后面添加一个“/”。

选择2对我来说是可行的。我去了窗口>首选项>安装/更新>可用的软件网站，然后为每个启用的网站，我在URL的末尾添加了一个/(如果它还没有)，然后单击重新加载。

简单! !

右键单击eclipse文件夹并进入属性。 取消选中“只读”复选框。 应用更改。单击oK。

>安装新软件>取消勾选“安装期间联系所有更新站点以查找所需软件”。

问题似乎是与窗口->首选项->可用软件网站中列出的过时网站。在这个窗口中，只需更新建造地点的位置。

对于建筑，不同版本的正确url可以从这个主站点找到: https://download.eclipse.org/buildship/updates/

对于特定版本，请继续向下导航，直到到达特定版本。 例如:https://download.eclipse.org/buildship/updates/e416/releases/3.x/

如需最新更新，请使用url https://download.eclipse.org/buildship/updates/latest/

求助→安装新软件→这里取消勾选“安装期间联系所有更新站点以查找所需软件”

Eclipse将提示内容未经授权或类似的内容。忽略它，继续。那么一切都会好的。

至少这个技巧解决了我类似这样的问题:

An error occurred while collecting items to be installed session
context was:(profile=epp.package.jee,
phase=org.eclipse.equinox.internal.p2.engine.phases.Collect, operand=,
action=). No repository found containing:
osgi.bundle,org.eclipse.emf,2.6.0.v20120917-0436 No repository found
containing: osgi.bundle,org.eclipse.emf.ant,2.7.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.codegen,2.8.0.v20120917-0436 No repository
found containing:
osgi.bundle,org.eclipse.emf.codegen.ecore,2.8.1.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.codegen.ecore.ui,2.8.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.codegen.ui,2.6.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.common,2.8.0.v20120911-0500 No repository
found containing:
osgi.bundle,org.eclipse.emf.common.ui,2.7.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.converter,2.5.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.databinding,1.2.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.databinding.edit,1.2.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.ecore,2.8.1.v20120911-0500 No repository
found containing:
osgi.bundle,org.eclipse.emf.ecore.change,2.8.0.v20120911-0500 No
repository found containing:
osgi.bundle,org.eclipse.emf.ecore.change.edit,2.5.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.ecore.edit,2.8.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.ecore.editor,2.8.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.ecore.xmi,2.8.0.v20120911-0500 No
repository found containing:
osgi.bundle,org.eclipse.emf.edit,2.8.0.v20120917-0436 No repository
found containing:
osgi.bundle,org.eclipse.emf.edit.ui,2.8.0.v20120917-0436 No repository
found containing:
osgi.bundle,org.eclipse.emf.exporter,2.6.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.importer,2.7.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.importer.ecore,2.6.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.importer.java,2.6.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.importer.rose,2.6.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.mapping,2.7.0.v20120917-0436 No repository
found containing:
osgi.bundle,org.eclipse.emf.mapping.ecore,2.6.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.mapping.ecore.editor,2.6.0.v20120917-0436
No repository found containing:
osgi.bundle,org.eclipse.emf.mapping.ecore2ecore,2.7.0.v20120917-0436
No repository found containing:
osgi.bundle,org.eclipse.emf.mapping.ecore2ecore.editor,2.5.0.v20120917-0436
No repository found containing:
osgi.bundle,org.eclipse.emf.mapping.ecore2xml,2.7.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.emf.mapping.ecore2xml.ui,2.6.0.v20120917-0436
No repository found containing:
osgi.bundle,org.eclipse.emf.mapping.ui,2.6.0.v20120917-0436 No
repository found containing:
osgi.bundle,org.eclipse.wst.common.project.facet.core,1.4.300.v201111030424
No repository found containing:
osgi.bundle,org.eclipse.wst.common.project.facet.ui,1.4.300.v201111030424
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.codegen.ecore,2.8.1.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.codegen.ecore.ui,2.8.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.codegen,2.8.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.codegen.ui,2.7.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.common,2.8.0.v20120911-0500
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.common.ui,2.7.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.converter,2.8.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.databinding.edit,1.2.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.databinding,1.2.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.ecore.edit,2.8.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.ecore.editor,2.8.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.ecore,2.8.1.v20120911-0500
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.edit,2.8.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.edit.ui,2.8.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf,2.8.1.v20120917-0436 No
repository found containing:
org.eclipse.update.feature,org.eclipse.emf.mapping.ecore.editor,2.7.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.mapping.ecore,2.7.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.mapping,2.7.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.emf.mapping.ui,2.7.0.v20120917-0436
No repository found containing:
org.eclipse.update.feature,org.eclipse.wst.common.fproj,3.4.0.v201202292300-377F8N8s735555393B7B

对于Eclipse Neon，我有提到Mylyn的错误。

为了使它工作，我必须启用Mylyn站点，这些站点在Available Software Sites首选项窗格中被禁用。它们没有命名(空名称)，但是可以通过Location列来识别。

保存、更新Mylyn并重新启动eclipse后，可用软件站点如下所示:

其他的答案都不适合我(Windows 10, Eclipse Neon)。以管理员身份运行Eclipse解决了这个问题。