如前所述，转换为XML有严格的规则，当HTML neglet编写结束标记</tr>时，将其加载为xml将失败。对于没有结束标记</img>的<img>标记也是如此。
我没有你正在加载的完整HTML，但也许可以尝试下面的函数：

function ConvertFrom_HtmlTable {
    # adapted from: https://www.leeholmes.com/blog/2015/01/05/extracting-tables-from-powershells-invoke-webrequest/
    [CmdletBinding(DefaultParameterSetName = 'ByIndex')]
    param(
        [Parameter(Mandatory = $true, Position = 0)]
        [Microsoft.PowerShell.Commands.HtmlWebResponseObject]$WebRequest,

        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ByIndex')]
        [int]$TableIndex = 0,

        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ById')]
        [string]$TableId,

        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ByName')]
        [string]$TableName,

        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ByClass')]
        [string]$TableClassName
    )

    # Extract the table out of the web request
    switch ($PSCmdlet.ParameterSetName) {
        'ById'    { $table = $WebRequest.ParsedHtml.getElementByID($TableId) }
        'ByIndex' { $table = @($WebRequest.ParsedHtml.getElementsByTagName('table'))[$TableIndex]}
        'ByName'  { $table = @($WebRequest.ParsedHtml.getElementsByName($TableName))[0] }
        'ByClass' { $table = @($WebRequest.ParsedHtml.getElementsByClassName($TableClassName))[0] }
    }
    if (!$table) {
        Write-Warning "Could not find the given table."
        return $null
    }

    # load the System.Web assembly to be able to decode HTML entities
    Add-Type -AssemblyName System.Web

    $headers = @()
    # Go through all of the rows in the table
    foreach ($row in $table.Rows) {
        $cells = @($row.Cells)
        # If there is a table header, remember its titles
        if($cells[0].tagName -eq "TH") {
            $i = 0
            $headers = @($cells | ForEach-Object {
                $i++
                # decode HTML entities and double-up quotes that the value may contain
                $th = ([System.Web.HttpUtility]::HtmlDecode($_.InnerText) -replace '"', '""').Trim()
                # if the table header is empty, create it
                if ([string]::IsNullOrEmpty($th)) { "H$i" } else { $th }
            })
            # proceed with the next row
            continue
        }
        # if we haven't found any table headers, make up names "H1", "H2", etc.
        if(-not $headers) {
            $headers = @(1..($cells.Count + 2) | ForEach-Object { "H$_" })
        }

        # Now go through the cells in the the row. For each, try to find the
        # title that represents that column and create a hashtable mapping those
        # titles to content
        $hash = [Ordered]@{}
        for ($i = 0; $i -lt $cells.Count; $i++) {
            # decode HTML entities and double-up quotes that the value may contain
            $value = ([System.Web.HttpUtility]::HtmlDecode($cells[$i].InnerText) -replace '"', '""').Trim()
            $th = $headers[$i]
            $hash[$th] = $value.Trim()
        }
        # And finally cast that hashtable to a PSCustomObject
        [PSCustomObject]$hash
    }
}

这样称呼它：

$request = Invoke-WebRequest $uri
$table = ConvertFrom_HtmlTable -WebRequest $request -TableClassName 'organization-admin__table table'

或者如果您知道它是html中的第一个或第x个表，则使用TableIndex参数，因为它显然没有id或name
如果成功了，你可以简单地写到csv：

$table | Export-Csv -Path 'X:\path\to\theTable.csv' -NoTypeInformation

从您的评论来看，似乎出于某种原因，您不能使用Invoke-WebRequest，而必须使用IE com对象进行解析。
请尝试以下版本的函数：

function ConvertFrom_HtmlTable {
    [CmdletBinding(DefaultParameterSetName = 'ByIndex')]
    param(
        [Parameter(ValueFromPipeline = $true, Mandatory = $true, Position = 0)]
        [string]$Url,

        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ByIndex')]
        [int]$TableIndex = 0,

        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ById')]
        [string]$TableId,

        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ByName')]
        [string]$TableName,
    
        [Parameter(Mandatory = $false, Position = 1, ParameterSetName = 'ByClass')]
        [string]$TableClassName,

        [switch]$FirstRowHasHeaders
    )

    $ie = New-Object -ComObject 'InternetExplorer.Application'
    $ie.Visible = $false
    $ie.Silent = $true
    $ie.Navigate($Url)
    # wait for IE to fully load the document
    while($ie.Busy) { Start-Sleep -Milliseconds 100 }

    $doc = $ie.Document

    switch ($PSCmdlet.ParameterSetName) {
        'ById'    { $table = $doc.IHTMLDocument3_getElementByID($TableId) }
        'ByIndex' { $table = @($doc.IHTMLDocument3_getElementsByTagName('table'))[$TableIndex]}
        'ByName'  { $table = @($doc.IHTMLDocument3_getElementsByName($TableName))[0] }
        'ByClass' { $table = @($doc.IHTMLDocument3_getElementsByClassName($TableClassName))[0] }
    }

    if ($table) {
        # Extracting table rows as a collection.
        $tbody = $table.childNodes | Where-Object { $_.tagName -eq "tbody" }
        if ($tbody) {
            $rows = $tbody.childNodes | Where-Object { $_.tagName -eq "tr" }
        }
        else {
            $rows = $table.childNodes | Where-Object { $_.tagName -eq "tr" }
        }

        # read or create table headers
        # assume the first row has headers either in <th> or <td> tags
        $firstRow = 1
        $headers = @($rows[0].childNodes | Where-Object { $_.tagName -eq "th" } | Foreach-Object { $_.innerHTML })

        if (!($headers)) {
            # there were no <th> tags found, so either use the first row as headers or create from scratch
            $values = @($rows[0].childNodes | Where-Object { $_.tagName -eq "td" } | Foreach-Object { $_.innerHTML })
            if ($FirstRowHasHeaders) {
                # the headers are considered to be the values from the first row
                $headers = $values
            }
            else {
                # the table has no headers, so dynamically create them
                $firstRow = 0
                $headers =  for ($i = 1; $i -le $values.Count; $i++) { "Column_$i" }
            }
        }

        # create a List object to store the values found as PSObjects
        $result = [System.Collections.Generic.List[object]]::new()
        for ($i = $firstRow; $i -lt $rows.Count; $i++) {
            $values = @($rows[$i].childNodes | Where-Object { $_.tagName -eq "td" } | Foreach-Object { $_.innerHTML })
            $valuesCount = $values.Count
            while ($headers.Count -lt $valuesCount) {
                $colName = "Column_{0}" -f ($headers.Count + 1)
                $headers += $colName
                # we have just added a new header column. Make sure the first item also has this new column
                if ($result.Count) { 
                    $result[0] | Add-Member -MemberType NoteProperty -Name $colName -Value $null
                }
            }
            # create a Hashtable to get store the values
            $data = [ordered]@{}
            for ($j = 0; $j -lt $valuesCount; $j++) { $data[$headers[$j]] = $values[$j] }
            # add the hash cast to PsCustomObject to the list
            $result.Add(([PsCustomObject]$data))
        }
    }
    else { Write-Warning "Could not find the given table." }

    # quit IE and clean up
    $ie.Quit()
    $null = [System.Runtime.Interopservices.Marshal]::ReleaseComObject($ie)
    [System.GC]::Collect()
    [System.GC]::WaitForPendingFinalizers()

    return $result
}

$table = ConvertFrom_HtmlTable -Url 'your URL here' -TableClassName 'organization-admin__table'
$table | Export-Csv -Path 'X:\path\to\theTable.csv' -NoTypeInformation

使用InternetExplorer.Application COM对象的第二个函数需要使用DOM查找表对象。为此，该函数目前使用IHTMLDocument3 interface，对我来说，在Windows 10 Pro，PowerShell 5.1和IE版本11.789.19041.0上进行测试时，例如

ConvertFrom_HtmlTable -Url 'https://www.w3schools.com/html/html_tables.asp' -TableId 'customers'

根据您的评论，您收到错误消息：
方法调用失败，因为[mshtml.HTMLDocumentClass]不包含名为“IHTMLDocument3_getElementsByClassName”的方法。
这意味着您的机器上有一个不同的（未更新/损坏）版本，您必须自己尝试哪种方法有效：
1.首先通过在PowerShell控制台中键入以下内容来测试您的IE版本：

(Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Internet Explorer').SvcVersion

如果返回空白，请尝试

(Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Internet Explorer').Version

1.接下来，在switch中更改从

$doc.IHTMLDocument3_getElementsByClassName($TableClassName)

到

$doc.getElementsByClassName($TableClassName)

或

$doc.documentElement.getElementsByClassName($TableClassName)

如果所有这些都失败了，恐怕你的计算机上有一个严重的问题（也许Invoke-Webrequest也不工作的原因？））。尝试使用fsc /scannow解决此问题

我想用一个表转换一个本地HTML文件。我也没有安装IE，所以我对上面Theo的伟大答案做了以下更新，它起作用了：
变更：

$ie = New-Object -ComObject 'InternetExplorer.Application'
$ie.Visible = $false
$ie.Silent = $true
$ie.Navigate($Url)
# wait for IE to fully load the document
while($ie.Busy) { Start-Sleep -Milliseconds 100 }

$doc = $ie.Document

到

$Source = Get-Content -path $Url -raw
$HTML = New-Object -Com "HTMLFile"
$HTML.IHTMLDocument2_write($Source)

$doc = $HTML.childNodes.ie9_item().document

并移除

$ie.Quit()
$null = [System.Runtime.Interopservices.Marshal]::ReleaseComObject($ie)