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。

我是在Eclipse中为Java EE开发人员Helios安装Maven支持时得到的。解决方案是以管理员身份运行Eclipse，之后就可以正常更新了

我帮助解决了以下问题:

Go to Help->Software Updates, then select the Available Software tab and click the Manage Sites button Use the Export button to export the sites to a bookmarks.xml file Open the bookmarks.xml file in your favorite text editor, and add a trailing “/” to any of the site urls which are missing the “/” or remove on the end. Save the changes. Back in the Manage Sites window within Eclipse, select all of the sites and click the Remove button Now, click Import and load in the edited bookmarks.xml file

是从这个链接截取的德文·希拉德的数字避难所

我使用lubuntu(像ubuntu)，我发现当我安装ccs时，我使用sudo cmd，所以一些文件不能由另一个用户更改，这就是问题出现的原因。所以在我安装ccs的地方，我运行cmd

sudo chown -R username:groupname * 

用户名和组名与我的计算机帐户相同。

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。

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